diff --git a/src/modules/classes/actions-shared.ts b/src/modules/classes/actions-shared.ts
index 3926d71..4167b7d 100644
--- a/src/modules/classes/actions-shared.ts
+++ b/src/modules/classes/actions-shared.ts
@@ -2,12 +2,10 @@ import { getTranslations } from "next-intl/server"
 
 import type { AuthContext } from "@/shared/types/permissions"
 import type { ClassSubject } from "./types"
-import { DEFAULT_CLASS_SUBJECTS } from "./types"
 import { ValidationError } from "@/shared/lib/action-utils"
-
-const CLASS_SUBJECT_STRINGS: readonly string[] = DEFAULT_CLASS_SUBJECTS
-
-export const isClassSubject = (v: string): v is ClassSubject => CLASS_SUBJECT_STRINGS.includes(v)
+// G3-036 去重：isClassSubject 已提取至 lib/admin-class-mappers，此处 re-export 保持向后兼容
+export { isClassSubject } from "./lib/admin-class-mappers"
+import { isClassSubject } from "./lib/admin-class-mappers"
 
 export const isWeekday = (n: number): n is 1 | 2 | 3 | 4 | 5 | 6 | 7 =>
   n >= 1 && n <= 7 && Number.isInteger(n)
diff --git a/src/modules/classes/components/admin-classes-view.tsx b/src/modules/classes/components/admin-classes-view.tsx
index cc85e0c..9a1e6fd 100644
--- a/src/modules/classes/components/admin-classes-view.tsx
+++ b/src/modules/classes/components/admin-classes-view.tsx
@@ -1,7 +1,7 @@
 "use client"
 
 import { useMemo } from "react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
 
@@ -43,14 +43,14 @@ export function AdminClassesClient({
     try {
       const res = await createAdminClassAction(undefined, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setCreateOpen(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedCreate"))
+        notify.error(res.message || t("list.failedCreate"))
       }
     } catch {
-      toast.error(t("list.failedCreate"))
+      notify.error(t("list.failedCreate"))
     } finally {
       data.setIsWorking(false)
     }
@@ -62,14 +62,14 @@ export function AdminClassesClient({
     try {
       const res = await updateAdminClassAction(data.editItem.id, undefined, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setEditItem(null)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedUpdate"))
+        notify.error(res.message || t("list.failedUpdate"))
       }
     } catch {
-      toast.error(t("list.failedUpdate"))
+      notify.error(t("list.failedUpdate"))
     } finally {
       data.setIsWorking(false)
     }
@@ -81,14 +81,14 @@ export function AdminClassesClient({
     try {
       const res = await deleteAdminClassAction(data.deleteItem.id)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setDeleteItem(null)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedDelete"))
+        notify.error(res.message || t("list.failedDelete"))
       }
     } catch {
-      toast.error(t("list.failedDelete"))
+      notify.error(t("list.failedDelete"))
     } finally {
       data.setIsWorking(false)
     }
diff --git a/src/modules/classes/components/class-detail/edit-class-dialog.tsx b/src/modules/classes/components/class-detail/edit-class-dialog.tsx
index e0c5fc9..a1dc282 100644
--- a/src/modules/classes/components/class-detail/edit-class-dialog.tsx
+++ b/src/modules/classes/components/class-detail/edit-class-dialog.tsx
@@ -2,7 +2,7 @@
 
 import { useState } from "react"
 import { useRouter } from "next/navigation"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useTranslations } from "next-intl"
 
 import { Button } from "@/shared/components/ui/button"
@@ -46,14 +46,14 @@ export function EditClassDialog({
     try {
       const res = await updateTeacherClassAction(classId, null, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onOpenChange(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedUpdate"))
+        notify.error(res.message || t("list.failedUpdate"))
       }
     } catch {
-      toast.error(t("list.failedUpdate"))
+      notify.error(t("list.failedUpdate"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/classes/components/class-invitation-manager.tsx b/src/modules/classes/components/class-invitation-manager.tsx
index 11e5674..709d3cb 100644
--- a/src/modules/classes/components/class-invitation-manager.tsx
+++ b/src/modules/classes/components/class-invitation-manager.tsx
@@ -3,7 +3,7 @@
 import * as React from "react"
 import { useQueryClient } from "@tanstack/react-query"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { Copy, Plus, Ban, Clock, Hash } from "lucide-react"
 
 import { Button } from "@/shared/components/ui/button"
@@ -85,9 +85,9 @@ export function ClassInvitationManager({
   const handleCopy = async (code: string): Promise<void> => {
     try {
       await navigator.clipboard.writeText(code)
-      toast.success(t("copied"))
+      notify.success(t("copied"))
     } catch {
-      toast.error(t("copy"))
+      notify.error(t("copy"))
     }
   }
 
@@ -240,7 +240,7 @@ function GenerateCodeDialog({ classId, onClose, onCreated }: GenerateCodeDialogP
       formData.set("note", note)
       const result = await createClassInvitationCodeAction(null, formData)
       if (result.success && result.data) {
-        toast.success(t("generateSuccess"))
+        notify.success(t("generateSuccess"))
         onCreated({
           id: result.data.id,
           code: result.data.code,
@@ -256,10 +256,10 @@ function GenerateCodeDialog({ classId, onClose, onCreated }: GenerateCodeDialogP
         })
         onClose()
       } else {
-        toast.error(result.message ?? t("generateFailed"))
+        notify.error(result.message ?? t("generateFailed"))
       }
     } catch {
-      toast.error(t("generateFailed"))
+      notify.error(t("generateFailed"))
     } finally {
       setIsSubmitting(false)
     }
diff --git a/src/modules/classes/components/grade-classes-view.tsx b/src/modules/classes/components/grade-classes-view.tsx
index 0d079e3..b140a57 100644
--- a/src/modules/classes/components/grade-classes-view.tsx
+++ b/src/modules/classes/components/grade-classes-view.tsx
@@ -1,7 +1,7 @@
 "use client"
 
 import { useMemo } from "react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
 
@@ -33,14 +33,14 @@ export function GradeClassesClient({
     try {
       const res = await createGradeClassAction(undefined, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setCreateOpen(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedCreate"))
+        notify.error(res.message || t("list.failedCreate"))
       }
     } catch {
-      toast.error(t("list.failedCreate"))
+      notify.error(t("list.failedCreate"))
     } finally {
       data.setIsWorking(false)
     }
@@ -52,14 +52,14 @@ export function GradeClassesClient({
     try {
       const res = await updateGradeClassAction(data.editItem.id, undefined, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setEditItem(null)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedUpdate"))
+        notify.error(res.message || t("list.failedUpdate"))
       }
     } catch {
-      toast.error(t("list.failedUpdate"))
+      notify.error(t("list.failedUpdate"))
     } finally {
       data.setIsWorking(false)
     }
@@ -71,14 +71,14 @@ export function GradeClassesClient({
     try {
       const res = await deleteGradeClassAction(data.deleteItem.id)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         data.setDeleteItem(null)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedDelete"))
+        notify.error(res.message || t("list.failedDelete"))
       }
     } catch {
-      toast.error(t("list.failedDelete"))
+      notify.error(t("list.failedDelete"))
     } finally {
       data.setIsWorking(false)
     }
diff --git a/src/modules/classes/components/my-classes-grid.tsx b/src/modules/classes/components/my-classes-grid.tsx
index c52ca3f..4b196d3 100644
--- a/src/modules/classes/components/my-classes-grid.tsx
+++ b/src/modules/classes/components/my-classes-grid.tsx
@@ -12,7 +12,7 @@ import {
   MapPin,
   GraduationCap,
 } from "lucide-react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import { Badge } from "@/shared/components/ui/badge"
@@ -65,15 +65,15 @@ export function MyClassesGrid({
     try {
       const res = await joinClassByInvitationCodeAction(null, formData)
       if (res.success) {
-        toast.success(res.message || t("invitation.joinSuccess"))
+        notify.success(res.message || t("invitation.joinSuccess"))
         setJoinOpen(false)
         setJoinSubject("")
         router.refresh()
       } else {
-        toast.error(res.message || t("invitation.joinFailed"))
+        notify.error(res.message || t("invitation.joinFailed"))
       }
     } catch {
-      toast.error(t("invitation.joinFailed"))
+      notify.error(t("invitation.joinFailed"))
     } finally {
       setIsWorking(false)
     }
@@ -220,13 +220,13 @@ function ClassTicket({
     try {
       const res = await ensureClassInvitationCodeAction(c.id)
       if (res.success) {
-        toast.success(res.message || t("invitation.generateSuccess"))
+        notify.success(res.message || t("invitation.generateSuccess"))
         router.refresh()
       } else {
-        toast.error(res.message || t("invitation.generateFailed"))
+        notify.error(res.message || t("invitation.generateFailed"))
       }
     } catch {
-      toast.error(t("invitation.generateFailed"))
+      notify.error(t("invitation.generateFailed"))
     } finally {
       onWorkingChange(false)
     }
@@ -237,13 +237,13 @@ function ClassTicket({
     try {
       const res = await regenerateClassInvitationCodeAction(c.id)
       if (res.success) {
-        toast.success(res.message || t("invitation.regenerateSuccess"))
+        notify.success(res.message || t("invitation.regenerateSuccess"))
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedRegenerate"))
+        notify.error(res.message || t("list.failedRegenerate"))
       }
     } catch {
-      toast.error(t("list.failedRegenerate"))
+      notify.error(t("list.failedRegenerate"))
     } finally {
       onWorkingChange(false)
     }
@@ -254,9 +254,9 @@ function ClassTicket({
     if (!code) return
     try {
       await navigator.clipboard.writeText(code)
-      toast.success(t("myClasses.codeCopied"))
+      notify.success(t("myClasses.codeCopied"))
     } catch {
-      toast.error(t("list.failedCopy"))
+      notify.error(t("list.failedCopy"))
     }
   }
 
diff --git a/src/modules/classes/components/schedule-create-dialog.tsx b/src/modules/classes/components/schedule-create-dialog.tsx
index 27b0081..852eaaf 100644
--- a/src/modules/classes/components/schedule-create-dialog.tsx
+++ b/src/modules/classes/components/schedule-create-dialog.tsx
@@ -3,7 +3,7 @@
 import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import {
@@ -58,14 +58,14 @@ export function ScheduleCreateDialog({
       formData.set("weekday", String(weekday))
       const res = await createClassScheduleItemAction(null, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onOpenChange(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedCreate"))
+        notify.error(res.message || t("list.failedCreate"))
       }
     } catch {
-      toast.error(t("list.failedCreate"))
+      notify.error(t("list.failedCreate"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/classes/components/schedule-delete-dialog.tsx b/src/modules/classes/components/schedule-delete-dialog.tsx
index 0ea6172..79babe5 100644
--- a/src/modules/classes/components/schedule-delete-dialog.tsx
+++ b/src/modules/classes/components/schedule-delete-dialog.tsx
@@ -3,7 +3,7 @@
 import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import {
   AlertDialog,
@@ -40,14 +40,14 @@ export function ScheduleDeleteDialog({
     try {
       const res = await deleteClassScheduleItemAction(deleteItem.id)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onClose()
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedDelete"))
+        notify.error(res.message || t("list.failedDelete"))
       }
     } catch {
-      toast.error(t("list.failedDelete"))
+      notify.error(t("list.failedDelete"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/classes/components/schedule-edit-dialog.tsx b/src/modules/classes/components/schedule-edit-dialog.tsx
index 6d4576e..feb7b7d 100644
--- a/src/modules/classes/components/schedule-edit-dialog.tsx
+++ b/src/modules/classes/components/schedule-edit-dialog.tsx
@@ -3,7 +3,7 @@
 import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import {
@@ -59,14 +59,14 @@ export function ScheduleEditDialog({
       formData.set("weekday", editWeekday)
       const res = await updateClassScheduleItemAction(editItem.id, null, formData)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onClose()
         router.refresh()
       } else {
-        toast.error(res.message || t("list.failedUpdate"))
+        notify.error(res.message || t("list.failedUpdate"))
       }
     } catch {
-      toast.error(t("list.failedUpdate"))
+      notify.error(t("list.failedUpdate"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/classes/components/students-table.tsx b/src/modules/classes/components/students-table.tsx
index 9c1a859..1e372f0 100644
--- a/src/modules/classes/components/students-table.tsx
+++ b/src/modules/classes/components/students-table.tsx
@@ -4,7 +4,7 @@ import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
 import { MoreHorizontal, UserCheck, UserX } from "lucide-react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import { Avatar, AvatarFallback, AvatarImage } from "@/shared/components/ui/avatar"
@@ -33,13 +33,13 @@ export function StudentsTable({ students }: { students: ClassStudent[] }) {
     try {
       const res = await setStudentEnrollmentStatusAction(student.classId, student.id, status)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         router.refresh()
       } else {
-        toast.error(res.message)
+        notify.error(res.message)
       }
     } catch {
-      toast.error(t("list.failedStatus"))
+      notify.error(t("list.failedStatus"))
     } finally {
       setWorkingKey(null)
     }
diff --git a/src/modules/classes/data-access-admin.ts b/src/modules/classes/data-access-admin.ts
index 2eb8291..1b80ea4 100644
--- a/src/modules/classes/data-access-admin.ts
+++ b/src/modules/classes/data-access-admin.ts
@@ -18,32 +18,30 @@ import {
 } from "@/shared/db/schema"
 import { ROLE_NAMES } from "@/shared/types/permissions"
 import { createModuleLogger } from "@/shared/lib/logger"
-import { DEFAULT_CLASS_SUBJECTS } from "./types"
 import type {
   AdminClassListItem,
-  ClassSubject,
-  ClassSubjectTeacherAssignment,
   CreateTeacherClassInput,
-  TeacherOption,
   UpdateTeacherClassInput,
 } from "./types"
 import {
-  compareClassLike,
   generateUniqueInvitationCode,
   getClassSubjects,
   isDuplicateInvitationCodeError,
 } from "./data-access"
+// G3-020 / G3-036 去重：isClassSubject / toClassSubject /
+// buildSubjectsByClassIdMap / composeAdminClassList 已提取至 lib/admin-class-mappers
+import {
+  buildSubjectsByClassIdMap,
+  composeAdminClassList,
+  type AdminClassRow,
+  type SubjectTeacherRow,
+} from "./lib/admin-class-mappers"
 
 const log = createModuleLogger("classes")
-const isClassSubject = (v: unknown): v is ClassSubject =>
-  typeof v === "string" && (DEFAULT_CLASS_SUBJECTS as readonly string[]).includes(v)
-
-const toClassSubject = (v: string): ClassSubject | null =>
-  isClassSubject(v) ? v : null
 
 export const getAdminClassesRaw = async (): Promise<AdminClassListItem[]> => {
   const [rows, subjectRows] = await Promise.all([
-    (async () => {
+    (async (): Promise<AdminClassRow[]> => {
       try {
         return await db
           .select({
@@ -138,53 +136,11 @@ export const getAdminClassesRaw = async (): Promise<AdminClassListItem[]> => {
       .from(classSubjectTeachers)
       .innerJoin(subjects, eq(subjects.id, classSubjectTeachers.subjectId))
       .leftJoin(users, eq(users.id, classSubjectTeachers.teacherId))
-      .orderBy(asc(classSubjectTeachers.classId), asc(subjects.name)),
+      .orderBy(asc(classSubjectTeachers.classId), asc(subjects.name)) as Promise<SubjectTeacherRow[]>,
   ])
 
-  const subjectsByClassId = new Map<string, Map<ClassSubject, TeacherOption | null>>()
-  for (const r of subjectRows) {
-    const subject = toClassSubject(r.subject)
-    if (!subject) continue
-    const teacher =
-      typeof r.teacherId === "string" && r.teacherId.length > 0
-        ? { id: r.teacherId, name: r.teacherName ?? "Unnamed", email: r.teacherEmail ?? "" }
-        : null
-    const bySubject = subjectsByClassId.get(r.classId) ?? new Map<ClassSubject, TeacherOption | null>()
-    bySubject.set(subject, teacher)
-    subjectsByClassId.set(r.classId, bySubject)
-  }
-
-  const list = rows.map((r) => {
-    const bySubject = subjectsByClassId.get(r.id)
-    const subjectTeachers: ClassSubjectTeacherAssignment[] = DEFAULT_CLASS_SUBJECTS.map((subject) => ({
-      subject,
-      teacher: bySubject?.get(subject) ?? null,
-    }))
-
-    return {
-      id: r.id,
-      schoolName: r.schoolName,
-      schoolId: r.schoolId,
-      name: r.name,
-      grade: r.grade,
-      gradeId: r.gradeId,
-      homeroom: r.homeroom,
-      room: r.room,
-      invitationCode: r.invitationCode ?? null,
-      teacher: {
-        id: r.teacherId,
-        name: r.teacherName ?? "Unnamed",
-        email: r.teacherEmail,
-      },
-      subjectTeachers,
-      studentCount: Number(r.studentCount ?? 0),
-      createdAt: r.createdAt.toISOString(),
-      updatedAt: r.updatedAt.toISOString(),
-    }
-  })
-
-  list.sort(compareClassLike)
-  return list
+  const subjectsByClassId = buildSubjectsByClassIdMap(subjectRows)
+  return composeAdminClassList(rows, subjectsByClassId)
 }
 export const getAdminClasses = cacheFn(getAdminClassesRaw, {
   tags: ["classes", "classes:list"],
@@ -203,7 +159,7 @@ export const getGradeManagedClassesRaw = async (userId: string): Promise<AdminCl
   const gradeIds = managedGradeIds.map((g) => g.id)
 
   const [rows, subjectRows] = await Promise.all([
-    (async () => {
+    (async (): Promise<AdminClassRow[]> => {
       try {
         return await db
           .select({
@@ -268,53 +224,11 @@ export const getGradeManagedClassesRaw = async (userId: string): Promise<AdminCl
       .innerJoin(classes, eq(classes.id, classSubjectTeachers.classId))
       .leftJoin(users, eq(users.id, classSubjectTeachers.teacherId))
       .where(inArray(classes.gradeId, gradeIds))
-      .orderBy(asc(classSubjectTeachers.classId), asc(subjects.name)),
+      .orderBy(asc(classSubjectTeachers.classId), asc(subjects.name)) as Promise<SubjectTeacherRow[]>,
   ])
 
-  const subjectsByClassId = new Map<string, Map<ClassSubject, TeacherOption | null>>()
-  for (const r of subjectRows) {
-    const subject = toClassSubject(r.subject)
-    if (!subject) continue
-    const teacher =
-      typeof r.teacherId === "string" && r.teacherId.length > 0
-        ? { id: r.teacherId, name: r.teacherName ?? "Unnamed", email: r.teacherEmail ?? "" }
-        : null
-    const bySubject = subjectsByClassId.get(r.classId) ?? new Map<ClassSubject, TeacherOption | null>()
-    bySubject.set(subject, teacher)
-    subjectsByClassId.set(r.classId, bySubject)
-  }
-
-  const list = rows.map((r) => {
-    const bySubject = subjectsByClassId.get(r.id)
-    const subjectTeachers: ClassSubjectTeacherAssignment[] = DEFAULT_CLASS_SUBJECTS.map((subject) => ({
-      subject,
-      teacher: bySubject?.get(subject) ?? null,
-    }))
-
-    return {
-      id: r.id,
-      schoolName: r.schoolName,
-      schoolId: r.schoolId,
-      name: r.name,
-      grade: r.grade,
-      gradeId: r.gradeId,
-      homeroom: r.homeroom,
-      room: r.room,
-      invitationCode: r.invitationCode ?? null,
-      teacher: {
-        id: r.teacherId,
-        name: r.teacherName ?? "Unnamed",
-        email: r.teacherEmail,
-      },
-      subjectTeachers,
-      studentCount: Number(r.studentCount ?? 0),
-      createdAt: r.createdAt.toISOString(),
-      updatedAt: r.updatedAt.toISOString(),
-    }
-  })
-
-  list.sort(compareClassLike)
-  return list
+  const subjectsByClassId = buildSubjectsByClassIdMap(subjectRows)
+  return composeAdminClassList(rows, subjectsByClassId)
 }
 export const getGradeManagedClasses = cacheFn(getGradeManagedClassesRaw, {
   tags: ["classes"],
diff --git a/src/modules/classes/data-access-students.ts b/src/modules/classes/data-access-students.ts
index c4bfa51..93cb0bb 100644
--- a/src/modules/classes/data-access-students.ts
+++ b/src/modules/classes/data-access-students.ts
@@ -282,9 +282,12 @@ export const getClassStudentsRaw = async (
     }
 
     if (q && q.length > 0) {
-      const needle = `%${q}%`
+      // F-02: 前缀匹配可走索引，避免 %xxx% 全表扫描；转义 LIKE 通配符
+      // MySQL 默认 collation（utf8mb4_*_ci）不区分大小写，无需 LOWER()
+      const escapeLike = (s: string) => s.replace(/[%_\\]/g, "\\$&")
+      const needle = `${escapeLike(q)}%`
       conditions.push(
-        sql`(LOWER(COALESCE(${users.name}, '')) LIKE ${needle} OR LOWER(${users.email}) LIKE ${needle})`
+        sql`(${users.name} LIKE ${needle} OR ${users.email} LIKE ${needle})`
       )
     }
 
diff --git a/src/modules/classes/data-access-teacher.ts b/src/modules/classes/data-access-teacher.ts
index d5db907..912fc26 100644
--- a/src/modules/classes/data-access-teacher.ts
+++ b/src/modules/classes/data-access-teacher.ts
@@ -37,13 +37,10 @@ import {
   generateUniqueInvitationCode,
   isDuplicateInvitationCodeError,
 } from "./data-access-invitations"
+// G3-036 去重：isClassSubject / toClassSubject 已提取至 lib/admin-class-mappers
+import { toClassSubject } from "./lib/admin-class-mappers"
 
 const log = createModuleLogger("classes")
-const isClassSubject = (v: unknown): v is ClassSubject =>
-  typeof v === "string" && (DEFAULT_CLASS_SUBJECTS as readonly string[]).includes(v)
-
-const toClassSubject = (v: string): ClassSubject | null =>
-  isClassSubject(v) ? v : null
 
 export const getTeacherClassesRaw = async (params?: { teacherId?: string }): Promise<TeacherClass[]> => {
   const teacherId = params?.teacherId ?? (await getSessionTeacherId())
@@ -90,13 +87,21 @@ export const getTeacherClassesRaw = async (params?: { teacherId?: string }): Pro
 
   list.sort(compareClassLike)
 
-  // Fetch recent assignments for trends and schedule
+  // N+1 优化：单条 SQL 获取所有可访问班级的课表，按 classId 分组到 Map，
+  // 替代原先每班级 1 条 SQL 的 N+1 模式。
+  const allSchedule = await getClassSchedule({ teacherId })
+  const scheduleByClassId = new Map<string, typeof allSchedule>()
+  for (const item of allSchedule) {
+    const arr = scheduleByClassId.get(item.classId) ?? []
+    arr.push(item)
+    scheduleByClassId.set(item.classId, arr)
+  }
+
+  // Fetch recent assignments for trends（getClassHomeworkInsights 已通过 cacheFn 缓存）
   const listWithTrends = await Promise.all(
     list.map(async (c) => {
-      const [insights, schedule] = await Promise.all([
-        getClassHomeworkInsights({ classId: c.id, teacherId, limit: 7 }),
-        getClassSchedule({ classId: c.id, teacherId }),
-      ])
+      const insights = await getClassHomeworkInsights({ classId: c.id, teacherId, limit: 7 })
+      const schedule = scheduleByClassId.get(c.id) ?? []
 
       const recentAssignments = insights
         ? insights.assignments.map((a) => ({
@@ -125,6 +130,32 @@ export const getTeacherClasses = cacheFn(getTeacherClassesRaw, {
   keyParts: ["classes", "teacher", "list"],
 })
 
+/**
+ * 批量获取多个班级的活跃学生 ID（Map<classId, studentId[]>）。
+ *
+ * 单条 `inArray` 查询替代 N 次 `getActiveStudentIdsByClassId` 调用，
+ * 供跨模块调用使用以消除 N+1 查询。
+ */
+export const getActiveStudentIdsByClassIdsBatch = async (
+  classIds: string[]
+): Promise<Map<string, string[]>> => {
+  const result = new Map<string, string[]>()
+  const uniqueIds = Array.from(new Set(classIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
+  if (uniqueIds.length === 0) return result
+
+  const rows = await db
+    .select({ classId: classEnrollments.classId, studentId: classEnrollments.studentId })
+    .from(classEnrollments)
+    .where(and(inArray(classEnrollments.classId, uniqueIds), eq(classEnrollments.status, "active")))
+
+  for (const r of rows) {
+    const list = result.get(r.classId) ?? []
+    list.push(r.studentId)
+    result.set(r.classId, list)
+  }
+  return result
+}
+
 export const getTeacherOptionsRaw = async (): Promise<TeacherOption[]> => {
   const rows = await db
     .select({ id: users.id, name: users.name, email: users.email })
@@ -345,99 +376,106 @@ export async function enrollTeacherByInvitationCode(
   if (!cls) throw new Error("Invalid invitation code")
   if (cls.teacherId === tid) return cls.id
 
-  const subjectValue = typeof subject === "string" ? subject.trim() : ""
-  const [existing] = await db
-    .select({ id: classSubjectTeachers.classId })
-    .from(classSubjectTeachers)
-    .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.teacherId, tid)))
-    .limit(1)
-
-  if (existing && !subjectValue) return cls.id
-  if (subjectValue) {
-    const [subRow] = await db.select({ id: subjects.id }).from(subjects).where(eq(subjects.name, subjectValue)).limit(1)
-    if (!subRow) throw new Error("Subject not found")
-    const sid = subRow.id
-
-    const [mapping] = await db
-      .select({ teacherId: classSubjectTeachers.teacherId })
+  // F-09：将多步读写包装在单事务中保证原子性，避免中途失败留下脏数据。
+  // 事务内统一使用 tx 执行查询，使读写看到一致的事务内状态。
+  // 返回 [classId, shouldConsume]：早退（已分配）场景不消耗邀请码，保留原行为。
+  const [enrolledClassId, shouldConsume] = await db.transaction<[string, boolean]>(async (tx) => {
+    const subjectValue = typeof subject === "string" ? subject.trim() : ""
+    const [existing] = await tx
+      .select({ id: classSubjectTeachers.classId })
       .from(classSubjectTeachers)
-      .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid)))
+      .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.teacherId, tid)))
       .limit(1)
 
-    if (mapping?.teacherId && mapping.teacherId !== tid) throw new Error("Subject already assigned")
-    if (mapping?.teacherId === tid) return cls.id
-    if (!mapping) {
-      await db
-        .insert(classSubjectTeachers)
-        .values({ classId: cls.id, subjectId: sid, teacherId: null })
-        .onDuplicateKeyUpdate({ set: { teacherId: sql`${classSubjectTeachers.teacherId}` } })
+    if (existing && !subjectValue) return [cls.id, false]
+    if (subjectValue) {
+      const [subRow] = await tx.select({ id: subjects.id }).from(subjects).where(eq(subjects.name, subjectValue)).limit(1)
+      if (!subRow) throw new Error("Subject not found")
+      const sid = subRow.id
+
+      const [mapping] = await tx
+        .select({ teacherId: classSubjectTeachers.teacherId })
+        .from(classSubjectTeachers)
+        .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid)))
+        .limit(1)
+
+      if (mapping?.teacherId && mapping.teacherId !== tid) throw new Error("Subject already assigned")
+      if (mapping?.teacherId === tid) return [cls.id, false]
+      if (!mapping) {
+        await tx
+          .insert(classSubjectTeachers)
+          .values({ classId: cls.id, subjectId: sid, teacherId: null })
+          .onDuplicateKeyUpdate({ set: { teacherId: sql`${classSubjectTeachers.teacherId}` } })
+      }
+
+      const [existingSubject] = await tx
+        .select({ id: classSubjectTeachers.classId })
+        .from(classSubjectTeachers)
+        .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), eq(classSubjectTeachers.teacherId, tid)))
+        .limit(1)
+
+      if (existingSubject) return [cls.id, false]
+
+      await tx
+        .update(classSubjectTeachers)
+        .set({ teacherId: tid })
+        .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), isNull(classSubjectTeachers.teacherId)))
+
+      const [assigned] = await tx
+        .select({ id: classSubjectTeachers.classId })
+        .from(classSubjectTeachers)
+        .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), eq(classSubjectTeachers.teacherId, tid)))
+        .limit(1)
+
+      if (!assigned) throw new Error("Subject already assigned")
+    } else {
+      const subjectRows = await tx
+        .select({ id: classSubjectTeachers.subjectId, name: subjects.name })
+        .from(classSubjectTeachers)
+        .innerJoin(subjects, eq(subjects.id, classSubjectTeachers.subjectId))
+        .where(and(eq(classSubjectTeachers.classId, cls.id), isNull(classSubjectTeachers.teacherId)))
+
+      const preferred = DEFAULT_CLASS_SUBJECTS.find((s) => subjectRows.some((r) => r.name === s))
+      if (!preferred) throw new Error("Class already has assigned teachers")
+      const subjectRow = subjectRows.find((r) => r.name === preferred)
+      if (!subjectRow) throw new Error("Subject not found")
+      const sid = subjectRow.id
+
+      await tx
+        .update(classSubjectTeachers)
+        .set({ teacherId: tid })
+        .where(
+          and(
+            eq(classSubjectTeachers.classId, cls.id),
+            eq(classSubjectTeachers.subjectId, sid),
+            isNull(classSubjectTeachers.teacherId)
+          )
+        )
+
+      const [assigned] = await tx
+        .select({ id: classSubjectTeachers.classId })
+        .from(classSubjectTeachers)
+        .where(
+          and(
+            eq(classSubjectTeachers.classId, cls.id),
+            eq(classSubjectTeachers.subjectId, sid),
+            eq(classSubjectTeachers.teacherId, tid)
+          )
+        )
+        .limit(1)
+
+      if (!assigned) throw new Error("Class already has assigned teachers")
     }
 
-    const [existingSubject] = await db
-      .select({ id: classSubjectTeachers.classId })
-      .from(classSubjectTeachers)
-      .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), eq(classSubjectTeachers.teacherId, tid)))
-      .limit(1)
+    return [cls.id, true]
+  })
 
-    if (existingSubject) return cls.id
-
-    await db
-      .update(classSubjectTeachers)
-      .set({ teacherId: tid })
-      .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), isNull(classSubjectTeachers.teacherId)))
-
-    const [assigned] = await db
-      .select({ id: classSubjectTeachers.classId })
-      .from(classSubjectTeachers)
-      .where(and(eq(classSubjectTeachers.classId, cls.id), eq(classSubjectTeachers.subjectId, sid), eq(classSubjectTeachers.teacherId, tid)))
-      .limit(1)
-
-    if (!assigned) throw new Error("Subject already assigned")
-  } else {
-    const subjectRows = await db
-      .select({ id: classSubjectTeachers.subjectId, name: subjects.name })
-      .from(classSubjectTeachers)
-      .innerJoin(subjects, eq(subjects.id, classSubjectTeachers.subjectId))
-      .where(and(eq(classSubjectTeachers.classId, cls.id), isNull(classSubjectTeachers.teacherId)))
-
-    const preferred = DEFAULT_CLASS_SUBJECTS.find((s) => subjectRows.some((r) => r.name === s))
-    if (!preferred) throw new Error("Class already has assigned teachers")
-    const subjectRow = subjectRows.find((r) => r.name === preferred)
-    if (!subjectRow) throw new Error("Subject not found")
-    const sid = subjectRow.id
-
-    await db
-      .update(classSubjectTeachers)
-      .set({ teacherId: tid })
-      .where(
-        and(
-          eq(classSubjectTeachers.classId, cls.id),
-          eq(classSubjectTeachers.subjectId, sid),
-          isNull(classSubjectTeachers.teacherId)
-        )
-      )
-
-    const [assigned] = await db
-      .select({ id: classSubjectTeachers.classId })
-      .from(classSubjectTeachers)
-      .where(
-        and(
-          eq(classSubjectTeachers.classId, cls.id),
-          eq(classSubjectTeachers.subjectId, sid),
-          eq(classSubjectTeachers.teacherId, tid)
-        )
-      )
-      .limit(1)
-
-    if (!assigned) throw new Error("Class already has assigned teachers")
-  }
-
-  // 消耗新表邀请码（旧表无计数，跳过）
-  if (result.codeId) {
+  // 消耗新表邀请码（旧表无计数，跳过） - 在事务外执行
+  if (shouldConsume && result.codeId) {
     await consumeInvitationCode(code)
   }
 
-  return cls.id
+  return enrolledClassId
 }
 
 export async function updateTeacherClass(classId: string, data: UpdateTeacherClassInput): Promise<void> {
diff --git a/src/modules/classes/data-access.ts b/src/modules/classes/data-access.ts
index 63c1fea..2ab96f6 100644
--- a/src/modules/classes/data-access.ts
+++ b/src/modules/classes/data-access.ts
@@ -3,6 +3,7 @@ import "server-only";
 import { and, asc, eq, inArray } from "drizzle-orm"
 
 import { db } from "@/shared/db"
+import { cacheFn } from "@/shared/lib/cache"
 import {
   classes,
   classEnrollments,
@@ -14,6 +15,9 @@ import {
 import { ROLE_NAMES } from "@/shared/types/permissions"
 import { DEFAULT_CLASS_SUBJECTS } from "./types"
 
+/** F-05: 列表查询默认上限，防止无界查询拉爆内存 */
+const DEFAULT_LIMIT = 1000
+
 export const getSessionTeacherId = async (): Promise<string | null> => {
   const { auth } = await import("@/auth")
   const session = await auth()
@@ -36,7 +40,7 @@ export const getTeacherIdForMutations = async (): Promise<string> => {
   return teacherId
 }
 
-export const getClassSubjects = async (): Promise<string[]> => {
+export const getClassSubjectsRaw = async (): Promise<string[]> => {
   const rows = await db.query.subjects.findMany({
     orderBy: (subjects, { asc }) => [asc(subjects.order), asc(subjects.name)],
   })
@@ -45,6 +49,11 @@ export const getClassSubjects = async (): Promise<string[]> => {
   // P1-5: subjects 表为空时回退到默认科目列表，避免班级创建流程中断
   return Array.from(new Set(names.length > 0 ? names : DEFAULT_CLASS_SUBJECTS))
 }
+export const getClassSubjects = cacheFn(getClassSubjectsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassSubjects"],
+})
 
 const normalizeSortText = (v: string | null | undefined): string =>
   typeof v === "string" ? v.trim().toLowerCase() : ""
@@ -80,7 +89,7 @@ export const compareClassLike = (
   return normalizeSortText(a.room).localeCompare(normalizeSortText(b.room))
 }
 
-export const getAccessibleClassIdsForTeacher = async (teacherId: string): Promise<string[]> => {
+export const getAccessibleClassIdsForTeacherRaw = async (teacherId: string): Promise<string[]> => {
   const [ownedIds, assignedIds] = await Promise.all([
     db.select({ id: classes.id }).from(classes).where(eq(classes.teacherId, teacherId)),
     db
@@ -90,6 +99,11 @@ export const getAccessibleClassIdsForTeacher = async (teacherId: string): Promis
   ])
   return Array.from(new Set([...ownedIds.map((x) => x.id), ...assignedIds.map((x) => x.id)]))
 }
+export const getAccessibleClassIdsForTeacher = cacheFn(getAccessibleClassIdsForTeacherRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getAccessibleClassIdsForTeacher"],
+})
 
 /**
  * Verify that a teacher owns a class (teacherId match on classes row).
@@ -104,7 +118,7 @@ export async function verifyTeacherOwnsClass(classId: string, teacherId: string)
   return Boolean(owned)
 }
 
-export const getClassGradeIdsByClassIds = async (classIds: string[]): Promise<Map<string, string>> => {
+export const getClassGradeIdsByClassIdsRaw = async (classIds: string[]): Promise<Map<string, string>> => {
   if (classIds.length === 0) return new Map()
   const rows = await db
     .select({ id: classes.id, gradeId: classes.gradeId })
@@ -118,20 +132,30 @@ export const getClassGradeIdsByClassIds = async (classIds: string[]): Promise<Ma
   }
   return map
 }
+export const getClassGradeIdsByClassIds = cacheFn(getClassGradeIdsByClassIdsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassGradeIdsByClassIds"],
+})
 
-export const getTeacherSubjectIdsForClass = async (teacherId: string, classId: string): Promise<string[]> => {
+export const getTeacherSubjectIdsForClassRaw = async (teacherId: string, classId: string): Promise<string[]> => {
   const rows = await db
     .select({ subjectId: classSubjectTeachers.subjectId })
     .from(classSubjectTeachers)
     .where(and(eq(classSubjectTeachers.teacherId, teacherId), eq(classSubjectTeachers.classId, classId)))
   return Array.from(new Set(rows.map((r) => String(r.subjectId))))
 }
+export const getTeacherSubjectIdsForClass = cacheFn(getTeacherSubjectIdsForClassRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getTeacherSubjectIdsForClass"],
+})
 
 /**
  * 获取班级的教师 ID（班主任）。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassTeacherById = async (classId: string): Promise<string | null> => {
+export const getClassTeacherByIdRaw = async (classId: string): Promise<string | null> => {
   const [row] = await db
     .select({ teacherId: classes.teacherId })
     .from(classes)
@@ -139,24 +163,34 @@ export const getClassTeacherById = async (classId: string): Promise<string | nul
     .limit(1)
   return row?.teacherId ?? null
 }
+export const getClassTeacherById = cacheFn(getClassTeacherByIdRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassTeacherById"],
+})
 
 /**
  * 获取班级所有学生 ID（不限状态）。
  * 供跨模块调用使用，避免直接查询 classEnrollments 表。
  */
-export const getStudentIdsByClassId = async (classId: string): Promise<string[]> => {
+export const getStudentIdsByClassIdRaw = async (classId: string): Promise<string[]> => {
   const rows = await db
     .select({ studentId: classEnrollments.studentId })
     .from(classEnrollments)
     .where(eq(classEnrollments.classId, classId))
   return rows.map((r) => r.studentId)
 }
+export const getStudentIdsByClassId = cacheFn(getStudentIdsByClassIdRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getStudentIdsByClassId"],
+})
 
 /**
  * 获取多个班级的所有学生 ID（不限状态）。
  * 供跨模块调用使用，避免直接查询 classEnrollments 表。
  */
-export const getStudentIdsByClassIds = async (classIds: string[]): Promise<string[]> => {
+export const getStudentIdsByClassIdsRaw = async (classIds: string[]): Promise<string[]> => {
   if (classIds.length === 0) return []
   const rows = await db
     .select({ studentId: classEnrollments.studentId })
@@ -164,24 +198,34 @@ export const getStudentIdsByClassIds = async (classIds: string[]): Promise<strin
     .where(inArray(classEnrollments.classId, classIds))
   return Array.from(new Set(rows.map((r) => r.studentId)))
 }
+export const getStudentIdsByClassIds = cacheFn(getStudentIdsByClassIdsRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getStudentIdsByClassIds"],
+})
 
 /**
  * 获取班级所有活跃学生 ID（status = 'active'）。
  * 供跨模块调用使用，避免直接查询 classEnrollments 表。
  */
-export const getActiveStudentIdsByClassId = async (classId: string): Promise<string[]> => {
+export const getActiveStudentIdsByClassIdRaw = async (classId: string): Promise<string[]> => {
   const rows = await db
     .select({ studentId: classEnrollments.studentId })
     .from(classEnrollments)
     .where(and(eq(classEnrollments.classId, classId), eq(classEnrollments.status, "active")))
   return rows.map((r) => r.studentId)
 }
+export const getActiveStudentIdsByClassId = cacheFn(getActiveStudentIdsByClassIdRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getActiveStudentIdsByClassId"],
+})
 
 /**
  * 获取班级所有活跃学生基本信息（id/name/email），按姓名升序。
  * 供跨模块调用使用（如考勤点名），避免直接查询 classEnrollments 表。
  */
-export const getClassActiveStudentsWithInfo = async (
+export const getClassActiveStudentsWithInfoRaw = async (
   classId: string
 ): Promise<Array<{ id: string; name: string; email: string }>> => {
   const rows = await db
@@ -192,20 +236,30 @@ export const getClassActiveStudentsWithInfo = async (
     .orderBy(asc(users.name))
   return rows.map((r) => ({ id: r.id, name: r.name ?? "Unknown", email: r.email }))
 }
+export const getClassActiveStudentsWithInfo = cacheFn(getClassActiveStudentsWithInfoRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getClassActiveStudentsWithInfo"],
+})
 
 /**
  * 获取教师在一个班级所教的科目 ID 列表。
  * 参数顺序为 (classId, teacherId)，供跨模块调用使用。
  */
-export const getTeacherSubjectIdsByClass = async (classId: string, teacherId: string): Promise<string[]> => {
+export const getTeacherSubjectIdsByClassRaw = async (classId: string, teacherId: string): Promise<string[]> => {
   return getTeacherSubjectIdsForClass(teacherId, classId)
 }
+export const getTeacherSubjectIdsByClass = cacheFn(getTeacherSubjectIdsByClassRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getTeacherSubjectIdsByClass"],
+})
 
 /**
  * 获取多个班级的所有教师 ID（班主任 + 任课教师）。
  * 供跨模块调用使用，避免直接查询 classes / classSubjectTeachers 表。
  */
-export const getTeacherIdsByClassIds = async (classIds: string[]): Promise<string[]> => {
+export const getTeacherIdsByClassIdsRaw = async (classIds: string[]): Promise<string[]> => {
   if (classIds.length === 0) return []
   const [homeroomRows, subjectRows] = await Promise.all([
     db
@@ -226,12 +280,17 @@ export const getTeacherIdsByClassIds = async (classIds: string[]): Promise<strin
   }
   return Array.from(set)
 }
+export const getTeacherIdsByClassIds = cacheFn(getTeacherIdsByClassIdsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getTeacherIdsByClassIds"],
+})
 
 /**
  * 获取学生当前活跃班级的 ID。
  * 供跨模块调用使用，避免直接查询 classEnrollments 表。
  */
-export const getStudentActiveClassId = async (studentId: string): Promise<string | null> => {
+export const getStudentActiveClassIdRaw = async (studentId: string): Promise<string | null> => {
   const [row] = await db
     .select({ classId: classEnrollments.classId })
     .from(classEnrollments)
@@ -240,12 +299,17 @@ export const getStudentActiveClassId = async (studentId: string): Promise<string
     .limit(1)
   return row?.classId ?? null
 }
+export const getStudentActiveClassId = cacheFn(getStudentActiveClassIdRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getStudentActiveClassId"],
+})
 
 /**
  * 获取学生当前活跃班级的 ID 与名称（一次 JOIN 查询）。
  * 供跨模块调用使用，避免分别查询 classEnrollments 与 classes 表。
  */
-export const getStudentActiveClass = async (
+export const getStudentActiveClassRaw = async (
   studentId: string,
 ): Promise<{ classId: string; className: string } | null> => {
   const [row] = await db
@@ -257,12 +321,17 @@ export const getStudentActiveClass = async (
     .limit(1)
   return row ?? null
 }
+export const getStudentActiveClass = cacheFn(getStudentActiveClassRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getStudentActiveClass"],
+})
 
 /**
  * 获取学生当前活跃班级对应的年级 ID。
  * 供跨模块调用使用，避免直接查询 classEnrollments/classes 表。
  */
-export const getStudentActiveGradeId = async (studentId: string): Promise<string | null> => {
+export const getStudentActiveGradeIdRaw = async (studentId: string): Promise<string | null> => {
   const [row] = await db
     .select({ gradeId: classes.gradeId })
     .from(classEnrollments)
@@ -272,12 +341,17 @@ export const getStudentActiveGradeId = async (studentId: string): Promise<string
     .limit(1)
   return row?.gradeId ?? null
 }
+export const getStudentActiveGradeId = cacheFn(getStudentActiveGradeIdRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getStudentActiveGradeId"],
+})
 
 /**
  * 校验班级是否存在。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassExists = async (classId: string): Promise<boolean> => {
+export const getClassExistsRaw = async (classId: string): Promise<boolean> => {
   const [row] = await db
     .select({ id: classes.id })
     .from(classes)
@@ -285,12 +359,17 @@ export const getClassExists = async (classId: string): Promise<boolean> => {
     .limit(1)
   return Boolean(row)
 }
+export const getClassExists = cacheFn(getClassExistsRaw, {
+  tags: ["classes"],
+  ttl: 60,
+  keyParts: ["classes", "getClassExists"],
+})
 
 /**
  * 获取班级名称。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassNameById = async (classId: string): Promise<string | null> => {
+export const getClassNameByIdRaw = async (classId: string): Promise<string | null> => {
   const [row] = await db
     .select({ name: classes.name })
     .from(classes)
@@ -298,12 +377,17 @@ export const getClassNameById = async (classId: string): Promise<string | null>
     .limit(1)
   return row?.name ?? null
 }
+export const getClassNameById = cacheFn(getClassNameByIdRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassNameById"],
+})
 
 /**
  * 获取班级关联的年级 ID。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassGradeId = async (classId: string): Promise<string | null> => {
+export const getClassGradeIdRaw = async (classId: string): Promise<string | null> => {
   const [row] = await db
     .select({ gradeId: classes.gradeId })
     .from(classes)
@@ -311,12 +395,17 @@ export const getClassGradeId = async (classId: string): Promise<string | null> =
     .limit(1)
   return row?.gradeId ?? null
 }
+export const getClassGradeId = cacheFn(getClassGradeIdRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassGradeId"],
+})
 
 /**
  * 获取多个班级关联的年级 ID 列表（去重，过滤空值）。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getGradeIdsByClassIds = async (classIds: string[]): Promise<string[]> => {
+export const getGradeIdsByClassIdsRaw = async (classIds: string[]): Promise<string[]> => {
   if (classIds.length === 0) return []
   const rows = await db
     .selectDistinct({ gradeId: classes.gradeId })
@@ -326,12 +415,17 @@ export const getGradeIdsByClassIds = async (classIds: string[]): Promise<string[
     .map((r) => r.gradeId)
     .filter((id): id is string => typeof id === "string" && id.length > 0)
 }
+export const getGradeIdsByClassIds = cacheFn(getGradeIdsByClassIdsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getGradeIdsByClassIds"],
+})
 
 /**
  * 批量获取班级名称（Map<classId, name>）。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassNamesByIds = async (classIds: string[]): Promise<Map<string, string>> => {
+export const getClassNamesByIdsRaw = async (classIds: string[]): Promise<Map<string, string>> => {
   const result = new Map<string, string>()
   const uniqueIds = Array.from(new Set(classIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
   if (uniqueIds.length === 0) return result
@@ -344,25 +438,36 @@ export const getClassNamesByIds = async (classIds: string[]): Promise<Map<string
   for (const r of rows) result.set(r.id, r.name)
   return result
 }
+export const getClassNamesByIds = cacheFn(getClassNamesByIdsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassNamesByIds"],
+})
 
 /**
  * 获取指定年级下的所有班级（id + name）。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassesByGradeId = async (gradeId: string): Promise<Array<{ id: string; name: string }>> => {
+export const getClassesByGradeIdRaw = async (gradeId: string): Promise<Array<{ id: string; name: string }>> => {
   if (!gradeId) return []
   const rows = await db
     .select({ id: classes.id, name: classes.name })
     .from(classes)
     .where(eq(classes.gradeId, gradeId))
+    .limit(DEFAULT_LIMIT)
   return rows.map((r) => ({ id: r.id, name: r.name }))
 }
+export const getClassesByGradeId = cacheFn(getClassesByGradeIdRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassesByGradeId"],
+})
 
 /**
  * 获取多个年级下的所有班级 ID（供 grades 模块 grade_managed scope 过滤使用）。
  * 供跨模块调用使用，避免直接查询 classes 表。
  */
-export const getClassIdsByGradeIds = async (gradeIds: string[]): Promise<string[]> => {
+export const getClassIdsByGradeIdsRaw = async (gradeIds: string[]): Promise<string[]> => {
   const uniqueIds = Array.from(new Set(gradeIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
   if (uniqueIds.length === 0) return []
   const rows = await db
@@ -371,6 +476,11 @@ export const getClassIdsByGradeIds = async (gradeIds: string[]): Promise<string[
     .where(inArray(classes.gradeId, uniqueIds))
   return rows.map((r) => r.id)
 }
+export const getClassIdsByGradeIds = cacheFn(getClassIdsByGradeIdsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassIdsByGradeIds"],
+})
 
 /**
  * 构建一个 Drizzle 子查询 SQL，用于过滤 classId IN (SELECT id FROM classes WHERE grade_id IN (...))。
@@ -380,11 +490,137 @@ export const getClassIdsByGradeIdsSubquery = (gradeIds: string[]) => {
   return db.select({ id: classes.id }).from(classes).where(inArray(classes.gradeId, gradeIds))
 }
 
+// ---------------------------------------------------------------------------
+// Cross-module interfaces — scheduling selectors (avoid direct schema queries)
+// ---------------------------------------------------------------------------
+
+/** 班级轻量信息（供排课模块选择器使用） */
+export type ClassSchedulingOption = {
+  id: string
+  name: string
+  grade: string
+}
+
+/**
+ * 跨模块接口：获取所有班级的轻量信息（id/name/grade），供排课模块选择器使用。
+ *
+ * 避免 scheduling 模块直接查询 classes 表。
+ */
+export const getClassesForSchedulingRaw = async (): Promise<ClassSchedulingOption[]> => {
+  const rows = await db
+    .select({ id: classes.id, name: classes.name, grade: classes.grade })
+    .from(classes)
+    .orderBy(asc(classes.grade), asc(classes.name))
+    .limit(DEFAULT_LIMIT)
+  return rows.map((r) => ({ id: r.id, name: r.name, grade: r.grade }))
+}
+export const getClassesForScheduling = cacheFn(getClassesForSchedulingRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassesForScheduling"],
+})
+
+/** 班级科目分配（仅 subjectId + teacherId，科目名称需调用方通过 school 模块解析） */
+export type ClassSubjectAssignment = {
+  subjectId: string
+  teacherId: string | null
+}
+
+/**
+ * 跨模块接口：获取指定班级的科目-教师分配（仅 subjectId + teacherId）。
+ *
+ * 供 scheduling 模块获取班级科目任课教师，避免直查 classSubjectTeachers 表。
+ * 科目名称需调用方通过 school 模块 getSubjectNameMapByIds 解析。
+ */
+export const getClassSubjectAssignmentsByClassIdRaw = async (
+  classId: string
+): Promise<ClassSubjectAssignment[]> => {
+  const rows = await db
+    .select({
+      subjectId: classSubjectTeachers.subjectId,
+      teacherId: classSubjectTeachers.teacherId,
+    })
+    .from(classSubjectTeachers)
+    .where(eq(classSubjectTeachers.classId, classId))
+  return rows.map((r) => ({ subjectId: r.subjectId, teacherId: r.teacherId ?? null }))
+}
+export const getClassSubjectAssignmentsByClassId = cacheFn(getClassSubjectAssignmentsByClassIdRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getClassSubjectAssignmentsByClassId"],
+})
+
+/**
+ * 跨模块接口：获取所有班级-科目-教师分配中的去重教师 ID 列表。
+ *
+ * 供 scheduling 模块获取"有任课的教师"列表，避免直查 classSubjectTeachers 表。
+ * 教师详情需调用方通过 users 模块 getTeachersByIds 解析。
+ */
+export const getDistinctTeacherIdsFromAssignmentsRaw = async (): Promise<string[]> => {
+  const rows = await db
+    .selectDistinct({ teacherId: classSubjectTeachers.teacherId })
+    .from(classSubjectTeachers)
+    .limit(DEFAULT_LIMIT)
+  return rows
+    .map((r) => r.teacherId)
+    .filter((id): id is string => typeof id === "string" && id.length > 0)
+}
+export const getDistinctTeacherIdsFromAssignments = cacheFn(getDistinctTeacherIdsFromAssignmentsRaw, {
+  tags: ["classes"],
+  ttl: 300,
+  keyParts: ["classes", "getDistinctTeacherIdsFromAssignments"],
+})
+
 // Re-export from split files for backward compatibility
-export * from "./data-access-stats"
-export * from "./data-access-schedule"
-export * from "./data-access-students"
-export * from "./data-access-admin"
+// G3-048: 对导出数 < 15 的子文件改为显式 re-export，便于 IDE 跳转与命名冲突检测；
+// 导出数 >= 15 的子文件保留 export * 以避免遗漏符号（见下方注释）。
+export {
+  getClassHomeworkInsightsRaw,
+  getClassHomeworkInsights,
+  getGradeHomeworkInsightsRaw,
+  getGradeHomeworkInsights,
+  getClassesDashboardStatsRaw,
+  getClassesDashboardStats,
+} from "./data-access-stats"
+export type { ClassesDashboardStats } from "./data-access-stats"
+
+export {
+  getClassIdByScheduleId,
+  getStudentScheduleRaw,
+  getStudentSchedule,
+  getClassScheduleRaw,
+  getClassSchedule,
+} from "./data-access-schedule"
+
+export {
+  getStudentsSubjectScoresRaw,
+  getStudentsSubjectScores,
+  getClassStudentSubjectScoresV2Raw,
+  getClassStudentSubjectScoresV2,
+  getStudentClassesRaw,
+  getStudentClasses,
+  getStudentClassByIdRaw,
+  getStudentClassById,
+  getClassStudentsRaw,
+  getClassStudents,
+  getStudentScopeData,
+  getGradeIdsForStudentIds,
+} from "./data-access-students"
+
+export {
+  getAdminClassesRaw,
+  getAdminClasses,
+  getGradeManagedClassesRaw,
+  getGradeManagedClasses,
+  getManagedGradesRaw,
+  getManagedGrades,
+  createAdminClass,
+  updateAdminClass,
+  deleteAdminClass,
+} from "./data-access-admin"
+
+// 以下子文件导出数 >= 15（invitations 22 个、teacher 18 个），显式列举易遗漏，
+// 保留 export * 以保证完整性。详见 G3-048 审计建议。
 export * from "./data-access-invitations"
 export * from "./data-access-teacher"
 
diff --git a/src/modules/course-plans/components/course-plan-detail.tsx b/src/modules/course-plans/components/course-plan-detail.tsx
index 58435c9..59b4b6f 100644
--- a/src/modules/course-plans/components/course-plan-detail.tsx
+++ b/src/modules/course-plans/components/course-plan-detail.tsx
@@ -5,7 +5,7 @@ import { useState } from "react"
 import { useRouter } from "next/navigation"
 import Link from "next/link"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { ArrowLeft, Pencil, Plus, Trash2, Download } from "lucide-react"
 import {
   DndContext,
@@ -88,15 +88,15 @@ export function CoursePlanDetail({
     try {
       const res = await deleteCoursePlanAction(plan.id)
       if (res.success) {
-        toast.success(t("toast.deleted"))
+        notify.success(t("toast.deleted"))
         trackCoursePlanEvent("plan_deleted", { planId: plan.id })
         router.push(successHref ?? "/admin/course-plans")
         router.refresh()
       } else {
-        toast.error(res.message || t("toast.deleteFailed"))
+        notify.error(res.message || t("toast.deleteFailed"))
       }
     } catch {
-      toast.error(t("toast.deleteFailed"))
+      notify.error(t("toast.deleteFailed"))
     } finally {
       setIsWorking(false)
       setDeleteOpen(false)
@@ -128,14 +128,14 @@ export function CoursePlanDetail({
     try {
       const res = await bulkToggleItemsAction(Array.from(selectedIds), true)
       if (res.success) {
-        toast.success(t("toast.bulkMarked", { count: res.data ?? 0 }))
+        notify.success(t("toast.bulkMarked", { count: res.data ?? 0 }))
         setSelectedIds(new Set())
         router.refresh()
       } else {
-        toast.error(t("toast.bulkFailed"))
+        notify.error(t("toast.bulkFailed"))
       }
     } catch {
-      toast.error(t("toast.bulkFailed"))
+      notify.error(t("toast.bulkFailed"))
     } finally {
       setIsWorking(false)
     }
@@ -166,14 +166,14 @@ export function CoursePlanDetail({
     try {
       const res = await reorderCoursePlanItemsAction({ planId: plan.id, items })
       if (res.success) {
-        toast.success(t("detail.reorderSaved"))
+        notify.success(t("detail.reorderSaved"))
         trackCoursePlanEvent("items_reordered", { planId: plan.id, count: items.length })
         router.refresh()
       } else {
-        toast.error(t("detail.reorderFailed"))
+        notify.error(t("detail.reorderFailed"))
       }
     } catch {
-      toast.error(t("detail.reorderFailed"))
+      notify.error(t("detail.reorderFailed"))
     } finally {
       setIsWorking(false)
     }
@@ -200,10 +200,10 @@ export function CoursePlanDetail({
         },
         filename,
       )
-      toast.success(t("export.exported"))
+      notify.success(t("export.exported"))
       trackCoursePlanEvent("plan_exported", { planId: plan.id, format: "csv" })
     } catch {
-      toast.error(t("export.exportFailed"))
+      notify.error(t("export.exportFailed"))
     }
   }
 
diff --git a/src/modules/course-plans/components/course-plan-form.tsx b/src/modules/course-plans/components/course-plan-form.tsx
index 2a8238e..1ccf277 100644
--- a/src/modules/course-plans/components/course-plan-form.tsx
+++ b/src/modules/course-plans/components/course-plan-form.tsx
@@ -4,7 +4,7 @@ import type { JSX } from "react"
 import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardFooter, CardHeader, CardTitle } from "@/shared/components/ui/card"
@@ -92,19 +92,19 @@ export function CoursePlanForm({
             : null
 
       if (!res) {
-        toast.error(t("form.invalidState"))
+        notify.error(t("form.invalidState"))
         return
       }
 
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         router.push(successHref ?? "/admin/course-plans")
         router.refresh()
       } else {
-        toast.error(res.message || t("form.saveFailed"))
+        notify.error(res.message || t("form.saveFailed"))
       }
     } catch {
-      toast.error(t("form.saveFailed"))
+      notify.error(t("form.saveFailed"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/course-plans/components/course-plan-item-editor.tsx b/src/modules/course-plans/components/course-plan-item-editor.tsx
index c551883..5dcbdd6 100644
--- a/src/modules/course-plans/components/course-plan-item-editor.tsx
+++ b/src/modules/course-plans/components/course-plan-item-editor.tsx
@@ -4,7 +4,7 @@ import type { JSX } from "react"
 import { useState } from "react"
 import { useRouter } from "next/navigation"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { Check, Trash2, X } from "lucide-react"
 
 import { Button } from "@/shared/components/ui/button"
@@ -59,19 +59,19 @@ export function CoursePlanItemEditor({
             : null
 
       if (!res) {
-        toast.error(t("item.invalidState"))
+        notify.error(t("item.invalidState"))
         return
       }
 
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onOpenChange(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("item.saveFailed"))
+        notify.error(res.message || t("item.saveFailed"))
       }
     } catch {
-      toast.error(t("item.saveFailed"))
+      notify.error(t("item.saveFailed"))
     } finally {
       setIsWorking(false)
     }
@@ -83,14 +83,14 @@ export function CoursePlanItemEditor({
     try {
       const res = await deleteCoursePlanItemAction(item.id)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         onOpenChange(false)
         router.refresh()
       } else {
-        toast.error(res.message || t("item.deleteFailed"))
+        notify.error(res.message || t("item.deleteFailed"))
       }
     } catch {
-      toast.error(t("item.deleteFailed"))
+      notify.error(t("item.deleteFailed"))
     } finally {
       setIsWorking(false)
     }
@@ -102,13 +102,13 @@ export function CoursePlanItemEditor({
     try {
       const res = await toggleCoursePlanItemCompletedAction(item.id, !item.isCompleted)
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         router.refresh()
       } else {
-        toast.error(res.message || t("item.updateFailed"))
+        notify.error(res.message || t("item.updateFailed"))
       }
     } catch {
-      toast.error(t("item.updateFailed"))
+      notify.error(t("item.updateFailed"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/course-plans/components/template-picker-dialog.tsx b/src/modules/course-plans/components/template-picker-dialog.tsx
index 34edce3..8f56a14 100644
--- a/src/modules/course-plans/components/template-picker-dialog.tsx
+++ b/src/modules/course-plans/components/template-picker-dialog.tsx
@@ -4,7 +4,7 @@ import type { JSX } from "react"
 import { useEffect, useState } from "react"
 import { useTranslations } from "next-intl"
 import { useRouter } from "next/navigation"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { FileText, Loader2, Search } from "lucide-react"
 
 import { Button } from "@/shared/components/ui/button"
@@ -110,7 +110,7 @@ export function TemplatePickerDialog({
     try {
       const res = await copyCoursePlanAction(selectedId, [targetClassId])
       if (res.success && res.data && res.data.length > 0) {
-        toast.success(t("templates.cloneSuccess"))
+        notify.success(t("templates.cloneSuccess"))
         trackCoursePlanEvent("plan_created_from_template", {
           sourcePlanId: selectedId,
           newPlanId: res.data[0],
@@ -119,10 +119,10 @@ export function TemplatePickerDialog({
         router.push(`${successHref}/${res.data[0]}/edit`)
         router.refresh()
       } else {
-        toast.error(res.message || t("templates.cloneFailed"))
+        notify.error(res.message || t("templates.cloneFailed"))
       }
     } catch {
-      toast.error(t("templates.cloneFailed"))
+      notify.error(t("templates.cloneFailed"))
     } finally {
       setCloning(false)
     }
diff --git a/src/modules/course-plans/data-access.ts b/src/modules/course-plans/data-access.ts
index 2490f91..df18f52 100644
--- a/src/modules/course-plans/data-access.ts
+++ b/src/modules/course-plans/data-access.ts
@@ -7,6 +7,7 @@ import { and, asc, desc, eq, inArray, type SQL } from "drizzle-orm"
 import { db } from "@/shared/db"
 import { coursePlanItems, coursePlans } from "@/shared/db/schema"
 import { safeParseDate } from "@/shared/lib/action-utils"
+import { serializeDate as toIso, serializeDateRequired as toIsoRequired } from "@/shared/lib/date-utils"
 import { createModuleLogger } from "@/shared/lib/logger"
 import type {
   CoursePlan,
@@ -27,10 +28,6 @@ import type {
 } from "./schema"
 
 const log = createModuleLogger("course-plans")
-const toIso = (d: Date | null | undefined): string | null =>
-  d ? d.toISOString() : null
-
-const toIsoRequired = (d: Date): string => d.toISOString()
 
 type PlanRow = typeof coursePlans.$inferSelect
 
@@ -158,7 +155,25 @@ export const getCoursePlansRaw = async (params?: GetCoursePlansParams, scope?: C
       if (params?.status)
         conditions.push(eq(coursePlans.status, params.status))
 
-      const query = db.select().from(coursePlans)
+      const query = db.select({
+        id: coursePlans.id,
+        classId: coursePlans.classId,
+        subjectId: coursePlans.subjectId,
+        teacherId: coursePlans.teacherId,
+        academicYearId: coursePlans.academicYearId,
+        semester: coursePlans.semester,
+        totalHours: coursePlans.totalHours,
+        completedHours: coursePlans.completedHours,
+        weeklyHours: coursePlans.weeklyHours,
+        startDate: coursePlans.startDate,
+        endDate: coursePlans.endDate,
+        syllabus: coursePlans.syllabus,
+        objectives: coursePlans.objectives,
+        status: coursePlans.status,
+        createdBy: coursePlans.createdBy,
+        createdAt: coursePlans.createdAt,
+        updatedAt: coursePlans.updatedAt,
+      }).from(coursePlans)
       const rows = await (conditions.length > 0
         ? query.where(and(...conditions))
         : query
@@ -181,7 +196,25 @@ export const getCoursePlanByIdRaw = async (id: string, scope?: CoursePlanQuerySc
     try {
       const conditions: SQL[] = [eq(coursePlans.id, id), ...buildScopeCondition(scope)]
       const [planRow] = await db
-        .select()
+        .select({
+          id: coursePlans.id,
+          classId: coursePlans.classId,
+          subjectId: coursePlans.subjectId,
+          teacherId: coursePlans.teacherId,
+          academicYearId: coursePlans.academicYearId,
+          semester: coursePlans.semester,
+          totalHours: coursePlans.totalHours,
+          completedHours: coursePlans.completedHours,
+          weeklyHours: coursePlans.weeklyHours,
+          startDate: coursePlans.startDate,
+          endDate: coursePlans.endDate,
+          syllabus: coursePlans.syllabus,
+          objectives: coursePlans.objectives,
+          status: coursePlans.status,
+          createdBy: coursePlans.createdBy,
+          createdAt: coursePlans.createdAt,
+          updatedAt: coursePlans.updatedAt,
+        })
         .from(coursePlans)
         .where(and(...conditions))
         .limit(1)
@@ -191,7 +224,20 @@ export const getCoursePlanByIdRaw = async (id: string, scope?: CoursePlanQuerySc
       const enriched = await enrichPlanRow(planRow)
 
       const itemRows = await db
-        .select()
+        .select({
+          id: coursePlanItems.id,
+          planId: coursePlanItems.planId,
+          week: coursePlanItems.week,
+          topic: coursePlanItems.topic,
+          content: coursePlanItems.content,
+          hours: coursePlanItems.hours,
+          textbookChapter: coursePlanItems.textbookChapter,
+          notes: coursePlanItems.notes,
+          isCompleted: coursePlanItems.isCompleted,
+          completedAt: coursePlanItems.completedAt,
+          createdAt: coursePlanItems.createdAt,
+          updatedAt: coursePlanItems.updatedAt,
+        })
         .from(coursePlanItems)
         .where(eq(coursePlanItems.planId, id))
         .orderBy(asc(coursePlanItems.week), asc(coursePlanItems.createdAt))
@@ -323,14 +369,17 @@ export async function reorderCoursePlanItems(
 
   if (!existing) return
 
-  await Promise.all(
-    items.map((item) =>
-      db
-        .update(coursePlanItems)
-        .set({ week: item.week })
-        .where(eq(coursePlanItems.id, item.id))
+  // 单事务保证原子性（F-09），并行 UPDATE 提升吞吐。
+  await db.transaction(async (tx) => {
+    await Promise.all(
+      items.map((item) =>
+        tx
+          .update(coursePlanItems)
+          .set({ week: item.week })
+          .where(eq(coursePlanItems.id, item.id))
+      )
     )
-  )
+  })
 }
 
 /**
@@ -365,7 +414,25 @@ export async function copyCoursePlanToClasses(
   if (targetClassIds.length === 0) return []
 
   const [source] = await db
-    .select()
+    .select({
+      id: coursePlans.id,
+      classId: coursePlans.classId,
+      subjectId: coursePlans.subjectId,
+      teacherId: coursePlans.teacherId,
+      academicYearId: coursePlans.academicYearId,
+      semester: coursePlans.semester,
+      totalHours: coursePlans.totalHours,
+      completedHours: coursePlans.completedHours,
+      weeklyHours: coursePlans.weeklyHours,
+      startDate: coursePlans.startDate,
+      endDate: coursePlans.endDate,
+      syllabus: coursePlans.syllabus,
+      objectives: coursePlans.objectives,
+      status: coursePlans.status,
+      createdBy: coursePlans.createdBy,
+      createdAt: coursePlans.createdAt,
+      updatedAt: coursePlans.updatedAt,
+    })
     .from(coursePlans)
     .where(eq(coursePlans.id, sourcePlanId))
     .limit(1)
@@ -373,7 +440,20 @@ export async function copyCoursePlanToClasses(
   if (!source) return []
 
   const sourceItems = await db
-    .select()
+    .select({
+      id: coursePlanItems.id,
+      planId: coursePlanItems.planId,
+      week: coursePlanItems.week,
+      topic: coursePlanItems.topic,
+      content: coursePlanItems.content,
+      hours: coursePlanItems.hours,
+      textbookChapter: coursePlanItems.textbookChapter,
+      notes: coursePlanItems.notes,
+      isCompleted: coursePlanItems.isCompleted,
+      completedAt: coursePlanItems.completedAt,
+      createdAt: coursePlanItems.createdAt,
+      updatedAt: coursePlanItems.updatedAt,
+    })
     .from(coursePlanItems)
     .where(eq(coursePlanItems.planId, sourcePlanId))
 
@@ -450,7 +530,25 @@ export const getGradeCoursePlanProgressRaw = async (params: { gradeId: string })
 
     // 查询年级下所有教学计划（仅 course_plans 表）
     const planRows = await db
-      .select()
+      .select({
+        id: coursePlans.id,
+        classId: coursePlans.classId,
+        subjectId: coursePlans.subjectId,
+        teacherId: coursePlans.teacherId,
+        academicYearId: coursePlans.academicYearId,
+        semester: coursePlans.semester,
+        totalHours: coursePlans.totalHours,
+        completedHours: coursePlans.completedHours,
+        weeklyHours: coursePlans.weeklyHours,
+        startDate: coursePlans.startDate,
+        endDate: coursePlans.endDate,
+        syllabus: coursePlans.syllabus,
+        objectives: coursePlans.objectives,
+        status: coursePlans.status,
+        createdBy: coursePlans.createdBy,
+        createdAt: coursePlans.createdAt,
+        updatedAt: coursePlans.updatedAt,
+      })
       .from(coursePlans)
       .where(inArray(coursePlans.classId, classIds))
       .orderBy(desc(coursePlans.createdAt))
diff --git a/src/modules/dashboard/components/dashboard-time-range-filter.tsx b/src/modules/dashboard/components/dashboard-time-range-filter.tsx
index de91bf2..10041e4 100644
--- a/src/modules/dashboard/components/dashboard-time-range-filter.tsx
+++ b/src/modules/dashboard/components/dashboard-time-range-filter.tsx
@@ -11,6 +11,11 @@ import { useTranslations } from "next-intl"
 /** 时间范围选项 */
 export type TimeRange = "today" | "week" | "month"
 
+/** 类型守卫：判断字符串是否为合法的 TimeRange */
+function isTimeRange(v: string): v is TimeRange {
+  return v === "today" || v === "week" || v === "month"
+}
+
 const RANGE_OPTIONS: { value: TimeRange; icon: typeof CalendarDays }[] = [
   { value: "today", icon: CalendarDays },
   { value: "week", icon: CalendarRange },
@@ -30,7 +35,8 @@ export function DashboardTimeRangeFilter({ className }: { className?: string })
   const pathname = usePathname()
   const searchParams = useSearchParams()
 
-  const currentRange = (searchParams.get("range") as TimeRange | null) ?? "today"
+  const rawRange = searchParams.get("range")
+  const currentRange: TimeRange = rawRange && isTimeRange(rawRange) ? rawRange : "today"
 
   const handleRangeChange = useCallback(
     (range: TimeRange) => {
diff --git a/src/modules/dashboard/hooks/use-dashboard-preferences.ts b/src/modules/dashboard/hooks/use-dashboard-preferences.ts
index 28081df..1038eb8 100644
--- a/src/modules/dashboard/hooks/use-dashboard-preferences.ts
+++ b/src/modules/dashboard/hooks/use-dashboard-preferences.ts
@@ -17,7 +17,15 @@ function loadPreferences(role: DashboardRole): WidgetPreferences {
   if (typeof window === "undefined") return {}
   try {
     const stored = localStorage.getItem(`${STORAGE_KEY}-${role}`)
-    return stored ? (JSON.parse(stored) as WidgetPreferences) : {}
+    if (!stored) return {}
+    const parsed: unknown = JSON.parse(stored)
+    // 从 unknown 转换：localStorage 数据不可信，做字段类型校验
+    if (typeof parsed !== "object" || parsed === null) return {}
+    const result: Record<string, boolean> = {}
+    for (const [k, v] of Object.entries(parsed)) {
+      if (typeof v === "boolean") result[k] = v
+    }
+    return result
   } catch {
     return {}
   }
diff --git a/src/modules/dashboard/hooks/use-dashboard-realtime.ts b/src/modules/dashboard/hooks/use-dashboard-realtime.ts
index 093d69a..e891ffa 100644
--- a/src/modules/dashboard/hooks/use-dashboard-realtime.ts
+++ b/src/modules/dashboard/hooks/use-dashboard-realtime.ts
@@ -50,7 +50,9 @@ export function useDashboardRealtime<T = unknown>(
 
       eventSource.addEventListener(eventName, (event) => {
         try {
-          const data = JSON.parse(event.data) as T
+          const raw: unknown = JSON.parse(event.data)
+          // 从 unknown 转换：SSE 数据结构由后端保证，泛型 T 的运行时校验由调用方负责
+          const data = raw as T
           setLastMessage(data)
           setLastUpdatedAt(new Date())
         } catch {
diff --git a/src/modules/diagnostic/components/class-diagnostic-view.tsx b/src/modules/diagnostic/components/class-diagnostic-view.tsx
index 9fd1d9c..a53385a 100644
--- a/src/modules/diagnostic/components/class-diagnostic-view.tsx
+++ b/src/modules/diagnostic/components/class-diagnostic-view.tsx
@@ -3,7 +3,7 @@
 import { useState } from "react"
 import Link from "next/link"
 import { useRouter } from "next/navigation"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useTranslations } from "next-intl"
 import { Users, AlertTriangle, TrendingUp, FileText, Filter } from "lucide-react"
 
@@ -77,10 +77,10 @@ export function ClassDiagnosticView({ summary }: ClassDiagnosticViewProps) {
     const result = await service.generateClassReport(summary.classId, period)
     setIsGenerating(false)
     if (result.success) {
-      toast.success(result.message)
+      notify.success(result.message)
       router.refresh()
     } else {
-      toast.error(result.message || t("error.generateClassFailed"))
+      notify.error(result.message || t("error.generateClassFailed"))
     }
   }
 
@@ -103,11 +103,11 @@ export function ClassDiagnosticView({ summary }: ClassDiagnosticViewProps) {
       if (result.success && result.data) {
         setFilteredStudents(result.data)
       } else {
-        toast.error(result.message || t("error.loadFailed"))
+        notify.error(result.message || t("error.loadFailed"))
         setFilteredStudents(null)
       }
     } catch {
-      toast.error(t("error.loadFailed"))
+      notify.error(t("error.loadFailed"))
       setFilteredStudents(null)
     } finally {
       setIsFiltering(false)
diff --git a/src/modules/diagnostic/components/report-list.tsx b/src/modules/diagnostic/components/report-list.tsx
index d35156f..dbaa888 100644
--- a/src/modules/diagnostic/components/report-list.tsx
+++ b/src/modules/diagnostic/components/report-list.tsx
@@ -4,7 +4,7 @@ import { useState } from "react"
 import { useRouter, useSearchParams } from "next/navigation"
 import { useCallback } from "react"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { FileText, Trash2, Send, Download } from "lucide-react"
 
 import { Badge } from "@/shared/components/ui/badge"
@@ -88,11 +88,11 @@ export function ReportList({ reports }: ReportListProps) {
     const result = await service.publishReport(publishId)
     setIsBusy(false)
     if (result.success) {
-      toast.success(result.message)
+      notify.success(result.message)
       setPublishId(null)
       router.refresh()
     } else {
-      toast.error(result.message || t("error.publishFailed"))
+      notify.error(result.message || t("error.publishFailed"))
     }
   }
 
@@ -102,11 +102,11 @@ export function ReportList({ reports }: ReportListProps) {
     const result = await service.deleteReport(deleteId)
     setIsBusy(false)
     if (result.success) {
-      toast.success(result.message)
+      notify.success(result.message)
       setDeleteId(null)
       router.refresh()
     } else {
-      toast.error(result.message || t("error.deleteFailed"))
+      notify.error(result.message || t("error.deleteFailed"))
     }
   }
 
@@ -119,7 +119,7 @@ export function ReportList({ reports }: ReportListProps) {
     try {
       const result = await service.exportReport(reportId)
       if (!result.success || !result.data) {
-        toast.error(result.message || t("error.exportFailed"))
+        notify.error(result.message || t("error.exportFailed"))
         return
       }
       // base64 -> Blob -> 下载
@@ -139,9 +139,9 @@ export function ReportList({ reports }: ReportListProps) {
       a.click()
       document.body.removeChild(a)
       URL.revokeObjectURL(url)
-      toast.success(t("reportList.exportSuccess"))
+      notify.success(t("reportList.exportSuccess"))
     } catch {
-      toast.error(t("error.exportFailed"))
+      notify.error(t("error.exportFailed"))
     } finally {
       setIsBusy(false)
     }
diff --git a/src/modules/diagnostic/data-access.ts b/src/modules/diagnostic/data-access.ts
index e77a47a..1542e4f 100644
--- a/src/modules/diagnostic/data-access.ts
+++ b/src/modules/diagnostic/data-access.ts
@@ -1,7 +1,7 @@
 import "server-only"
 
 import { cacheFn } from "@/shared/lib/cache"
-import { and, desc, eq, inArray } from "drizzle-orm"
+import { and, desc, eq, inArray, sql } from "drizzle-orm"
 
 import { db } from "@/shared/db"
 import { knowledgePointMastery, knowledgePoints } from "@/shared/db/schema"
@@ -107,7 +107,11 @@ export async function updateMasteryFromSubmission(submissionId: string): Promise
 
   // 读取已有掌握度记录，累积计算（而非覆盖）
   const existingRows = await db
-    .select()
+    .select({
+      knowledgePointId: knowledgePointMastery.knowledgePointId,
+      totalQuestions: knowledgePointMastery.totalQuestions,
+      correctQuestions: knowledgePointMastery.correctQuestions,
+    })
     .from(knowledgePointMastery)
     .where(
       and(
@@ -192,7 +196,11 @@ export async function updateMasteryFromHomeworkSubmission(submissionId: string):
 
   // 读取已有掌握度记录，累积计算（而非覆盖）
   const existingRows = await db
-    .select()
+    .select({
+      knowledgePointId: knowledgePointMastery.knowledgePointId,
+      totalQuestions: knowledgePointMastery.totalQuestions,
+      correctQuestions: knowledgePointMastery.correctQuestions,
+    })
     .from(knowledgePointMastery)
     .where(
       and(
@@ -282,7 +290,11 @@ export async function updateMasteryFromExamScore(
 
   // 读取已有掌握度记录，累积计算
   const existingRows = await db
-    .select()
+    .select({
+      knowledgePointId: knowledgePointMastery.knowledgePointId,
+      totalQuestions: knowledgePointMastery.totalQuestions,
+      correctQuestions: knowledgePointMastery.correctQuestions,
+    })
     .from(knowledgePointMastery)
     .where(
       and(
@@ -551,3 +563,115 @@ export const getClassStudentsByKnowledgePoint = cacheFn(getClassStudentsByKnowle
   ttl: 300,
   keyParts: ["diagnostic", "getClassStudentsByKnowledgePoint"],
 })
+
+// ---------------------------------------------------------------------------
+// Cross-module batch interfaces — mastery by knowledge point id set
+// ---------------------------------------------------------------------------
+// 供 textbooks 模块知识图谱使用，避免直查 knowledgePointMastery 表。
+// 仅查询 knowledgePointMastery 表（diagnostic 模块自有），由调用方传入 kpIds。
+// ---------------------------------------------------------------------------
+
+/** 知识点掌握度快照（与 textbooks.MasteryInfo 结构兼容） */
+export type MasterySnapshot = {
+  masteryLevel: number
+  totalQuestions: number
+  correctQuestions: number
+  lastAssessedAt: Date
+}
+
+/**
+ * 跨模块接口：获取学生在指定知识点集合上的掌握度。
+ *
+ * 供 textbooks 模块知识图谱学生视图使用，避免直查 knowledgePointMastery 表。
+ *
+ * @param studentId 学生 ID
+ * @param knowledgePointIds 知识点 ID 列表
+ * @returns Map<knowledgePointId, MasterySnapshot>
+ */
+export const getStudentMasteryByKpIdsRaw = async (
+  studentId: string,
+  knowledgePointIds: string[]
+): Promise<Map<string, MasterySnapshot>> => {
+  const result = new Map<string, MasterySnapshot>()
+  const uniqueIds = Array.from(new Set(knowledgePointIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
+  if (uniqueIds.length === 0) return result
+
+  const rows = await db
+    .select({
+      knowledgePointId: knowledgePointMastery.knowledgePointId,
+      masteryLevel: knowledgePointMastery.masteryLevel,
+      totalQuestions: knowledgePointMastery.totalQuestions,
+      correctQuestions: knowledgePointMastery.correctQuestions,
+      lastAssessedAt: knowledgePointMastery.lastAssessedAt,
+    })
+    .from(knowledgePointMastery)
+    .where(and(
+      eq(knowledgePointMastery.studentId, studentId),
+      inArray(knowledgePointMastery.knowledgePointId, uniqueIds),
+    ))
+
+  for (const r of rows) {
+    result.set(r.knowledgePointId, {
+      masteryLevel: Number(r.masteryLevel),
+      totalQuestions: r.totalQuestions,
+      correctQuestions: r.correctQuestions,
+      lastAssessedAt: r.lastAssessedAt,
+    })
+  }
+  return result
+}
+export const getStudentMasteryByKpIds = cacheFn(getStudentMasteryByKpIdsRaw, {
+  tags: ["diagnostic"],
+  ttl: 300,
+  keyParts: ["diagnostic", "getStudentMasteryByKpIds"],
+})
+
+/**
+ * 跨模块接口：获取多个学生在指定知识点集合上的聚合掌握度（按知识点聚合）。
+ *
+ * 供 textbooks 模块知识图谱班级视图使用，避免直查 knowledgePointMastery 表。
+ * 聚合方式：AVG(masteryLevel) / SUM(totalQuestions) / SUM(correctQuestions) / MAX(lastAssessedAt)。
+ *
+ * @param studentIds 学生 ID 列表
+ * @param knowledgePointIds 知识点 ID 列表
+ * @returns Map<knowledgePointId, MasterySnapshot>
+ */
+export const getClassMasteryByKpIdsRaw = async (
+  studentIds: string[],
+  knowledgePointIds: string[]
+): Promise<Map<string, MasterySnapshot>> => {
+  const result = new Map<string, MasterySnapshot>()
+  const uniqueStudentIds = Array.from(new Set(studentIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
+  const uniqueKpIds = Array.from(new Set(knowledgePointIds.filter((v): v is string => typeof v === "string" && v.length > 0)))
+  if (uniqueStudentIds.length === 0 || uniqueKpIds.length === 0) return result
+
+  const rows = await db
+    .select({
+      knowledgePointId: knowledgePointMastery.knowledgePointId,
+      avgMastery: sql<number>`AVG(${knowledgePointMastery.masteryLevel})`,
+      totalQuestions: sql<number>`SUM(${knowledgePointMastery.totalQuestions})`,
+      correctQuestions: sql<number>`SUM(${knowledgePointMastery.correctQuestions})`,
+      lastAssessedAt: sql<Date>`MAX(${knowledgePointMastery.lastAssessedAt})`,
+    })
+    .from(knowledgePointMastery)
+    .where(and(
+      inArray(knowledgePointMastery.studentId, uniqueStudentIds),
+      inArray(knowledgePointMastery.knowledgePointId, uniqueKpIds),
+    ))
+    .groupBy(knowledgePointMastery.knowledgePointId)
+
+  for (const r of rows) {
+    result.set(r.knowledgePointId, {
+      masteryLevel: Number(r.avgMastery),
+      totalQuestions: Number(r.totalQuestions),
+      correctQuestions: Number(r.correctQuestions),
+      lastAssessedAt: r.lastAssessedAt,
+    })
+  }
+  return result
+}
+export const getClassMasteryByKpIds = cacheFn(getClassMasteryByKpIdsRaw, {
+  tags: ["diagnostic"],
+  ttl: 300,
+  keyParts: ["diagnostic", "getClassMasteryByKpIds"],
+})
diff --git a/src/modules/elective/components/elective-course-form.tsx b/src/modules/elective/components/elective-course-form.tsx
index 14dba8c..e64b005 100644
--- a/src/modules/elective/components/elective-course-form.tsx
+++ b/src/modules/elective/components/elective-course-form.tsx
@@ -4,7 +4,7 @@ import { useState } from "react"
 import { useRouter } from "next/navigation"
 import Link from "next/link"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardFooter, CardHeader, CardTitle } from "@/shared/components/ui/card"
@@ -70,21 +70,21 @@ export function ElectiveCourseForm({
             : null
 
       if (!res) {
-        toast.error(t("form.invalidFormState"))
+        notify.error(t("form.invalidFormState"))
         return
       }
 
       if (res.success) {
-        toast.success(res.message)
+        notify.success(res.message)
         // 根据 backHref 推断返回列表页路径
         const redirectBase = backHref?.includes("/teacher/") ? "/teacher/elective" : "/admin/elective"
         router.push(redirectBase)
         router.refresh()
       } else {
-        toast.error(res.message || t("form.saveFailed"))
+        notify.error(res.message || t("form.saveFailed"))
       }
     } catch {
-      toast.error(t("form.saveFailed"))
+      notify.error(t("form.saveFailed"))
     } finally {
       setIsWorking(false)
     }
diff --git a/src/modules/elective/components/elective-course-list.tsx b/src/modules/elective/components/elective-course-list.tsx
index cbfdabc..afb2ec1 100644
--- a/src/modules/elective/components/elective-course-list.tsx
+++ b/src/modules/elective/components/elective-course-list.tsx
@@ -4,7 +4,7 @@ import { useState, useTransition } from "react"
 import { useRouter } from "next/navigation"
 import Link from "next/link"
 import { useTranslations } from "next-intl"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { Plus, Pencil, Lock, Unlock, Shuffle, Trash2 } from "lucide-react"
 
 import { Badge } from "@/shared/components/ui/badge"
@@ -57,10 +57,10 @@ export function ElectiveCourseList({
       formData.set("courseId", courseId)
       const res = await action(null, formData)
       if (res.success) {
-        toast.success(res.message ?? successMsg)
+        notify.success(res.message ?? successMsg)
         router.refresh()
       } else {
-        toast.error(res.message ?? t("errors.unexpected"))
+        notify.error(res.message ?? t("errors.unexpected"))
       }
       setPendingId(null)
     })
@@ -73,10 +73,10 @@ export function ElectiveCourseList({
       formData.set("courseId", courseId)
       const res = await deleteElectiveCourseAction(null, formData)
       if (res.success) {
-        toast.success(res.message ?? t("actions.delete"))
+        notify.success(res.message ?? t("actions.delete"))
         router.refresh()
       } else {
-        toast.error(res.message ?? t("errors.unexpected"))
+        notify.error(res.message ?? t("errors.unexpected"))
       }
       setPendingId(null)
     })
diff --git a/src/modules/elective/components/student-selection-view.tsx b/src/modules/elective/components/student-selection-view.tsx
index e596c32..6d8b59f 100644
--- a/src/modules/elective/components/student-selection-view.tsx
+++ b/src/modules/elective/components/student-selection-view.tsx
@@ -2,7 +2,7 @@
 
 import { useState, useTransition } from "react"
 import { useRouter } from "next/navigation"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useTranslations } from "next-intl"
 import { BookOpen, CheckCircle2, XCircle } from "lucide-react"
 
@@ -70,7 +70,7 @@ export function StudentMySelectionsSection({
       }
       const res = await dropCourseAction(null, formData)
       if (res.success) {
-        toast.success(res.message || t("student.dropSuccess"))
+        notify.success(res.message || t("student.dropSuccess"))
         router.refresh()
         // 清空该课程的退课理由
         setDropReasonMap((prev) => {
@@ -79,7 +79,7 @@ export function StudentMySelectionsSection({
           return next
         })
       } else {
-        toast.error(res.message ?? t("errors.unexpected"))
+        notify.error(res.message ?? t("errors.unexpected"))
       }
       setPendingId(null)
     })
@@ -210,10 +210,10 @@ export function StudentAvailableCoursesSection({
       formData.set("courseId", courseId)
       const res = await selectCourseAction(null, formData)
       if (res.success) {
-        toast.success(res.message || t("student.selectSuccess"))
+        notify.success(res.message || t("student.selectSuccess"))
         router.refresh()
       } else {
-        toast.error(res.message ?? t("errors.unexpected"))
+        notify.error(res.message ?? t("errors.unexpected"))
       }
       setPendingId(null)
     })
diff --git a/src/modules/elective/data-access-operations.ts b/src/modules/elective/data-access-operations.ts
index 356ab68..62f867e 100644
--- a/src/modules/elective/data-access-operations.ts
+++ b/src/modules/elective/data-access-operations.ts
@@ -1,7 +1,7 @@
 import "server-only"
 
 import { createId } from "@paralleldrive/cuid2"
-import { and, asc, eq, inArray, sql, type SQL } from "drizzle-orm"
+import { and, asc, eq, inArray } from "drizzle-orm"
 import { getTranslations } from "next-intl/server"
 
 import { db } from "@/shared/db"
@@ -14,8 +14,18 @@ import { sendNotification } from "@/modules/notifications"
 
 import { getElectiveCreditLimit, getCapacityNotifyThreshold } from "./data-access-settings"
 import { getStudentGradeId } from "./data-access-selections"
+import {
+  hasAnyScheduleConflict,
+  parseSchedule,
+} from "./lib/schedule-conflict"
+import { buildLotteryRankCase, partitionLottery } from "./lib/lottery"
 import type { CourseSelectionStatus } from "./types"
 
+// A-02 修复：纯函数已抽离至 lib/，此处 re-export 保持向后兼容
+// （tests/integration/elective/elective-pure-functions.test.ts 仍从本文件导入）
+export { normalizeDay, parseSchedule, isScheduleConflict } from "./lib/schedule-conflict"
+export { buildLotteryRankCase } from "./lib/lottery"
+
 /**
  * 选课模块业务错误码（与 i18n key `errors.*` 对应）。
  * 由 actions 层根据 code 通过 getTranslations 翻译为用户可见文案。
@@ -45,94 +55,12 @@ export class ElectiveBusinessError extends BusinessError {
   }
 }
 
-/**
- * 构建 lotteryRank 的 CASE SQL 表达式（纯函数，便于测试 SQL 片段结构）。
- */
-export function buildLotteryRankCase(ids: string[], startRank: number): SQL {
-  const branches = ids.map(
-    (id, idx) => sql`WHEN ${id} THEN ${startRank + idx}`
-  )
-  return sql`CASE ${courseSelections.id} ${sql.join(branches, sql` `)} END`
-}
-
-/**
- * 星期字符串归一化映射（纯函数，便于测试）。
- * 支持中英文全称与缩写，统一映射为 1-7 数字字符串。
- */
-const DAY_NORMALIZE_MAP: Readonly<Record<string, string>> = Object.freeze({
-  // 中文
-  "周一": "1", "周二": "2", "周三": "3", "周四": "4",
-  "周五": "5", "周六": "6", "周日": "7", "周天": "7",
-  "星期一": "1", "星期二": "2", "星期三": "3", "星期四": "4",
-  "星期五": "5", "星期六": "6", "星期日": "7", "星期天": "7",
-  // 英文全称
-  monday: "1", tuesday: "2", wednesday: "3", thursday: "4",
-  friday: "5", saturday: "6", sunday: "7",
-  // 英文缩写
-  mon: "1", tue: "2", wed: "3", thu: "4",
-  fri: "5", sat: "6", sun: "7",
-})
-
-export function normalizeDay(day: string): string {
-  return DAY_NORMALIZE_MAP[day.toLowerCase()] ?? day
-}
-
-/**
- * 解析课程 schedule 字段为可比较的时间段数组（纯函数，便于测试）。
- *
- * 支持多时段（以逗号或分号分隔），例如：
- * - "周一 14:00-15:30"
- * - "Mon 14:00-15:30, Wed 16:00-17:30"
- * - "周一 14:00-15:30；周三 16:00-17:30"
- *
- * 返回空数组表示无法解析（不参与冲突检测）。
- */
-export function parseSchedule(
-  schedule: string | null
-): Array<{ day: string; start: string; end: string }> {
-  if (!schedule || schedule.length === 0) return []
-
-  // 按逗号、分号、中文分号拆分多个时段
-  const segments = schedule.split(/[,，;；]/).map((s) => s.trim()).filter(Boolean)
-  const result: Array<{ day: string; start: string; end: string }> = []
-
-  // 支持中英文星期与英文全称/缩写
-  const dayPattern = "周[一二三四五六日天]|星期[一二三四五六日天]|[Mm]on(?:day)?|[Tt]ue(?:sday)?|[Ww]ed(?:nesday)?|[Tt]hu(?:rsday)?|[Ff]ri(?:day)?|[Ss]at(?:urday)?|[Ss]un(?:day)?"
-  const timePattern = "(\\d{1,2}):(\\d{2})"
-  const re = new RegExp(
-    `^(${dayPattern})\\s+${timePattern}\\s*[-~～至到]\\s*${timePattern}$`,
-    "i"
-  )
-
-  for (const seg of segments) {
-    const match = seg.match(re)
-    if (!match) continue
-    const [, day, startH, startM, endH, endM] = match
-    if (!day || !startH || !startM || !endH || !endM) continue
-    result.push({
-      day,
-      start: `${startH.padStart(2, "0")}:${startM}`,
-      end: `${endH.padStart(2, "0")}:${endM}`,
-    })
-  }
-  return result
-}
-
-/**
- * 检测两组时间段是否存在冲突（纯函数，便于测试）。
- * 仅当 day 相同（归一化后）且时间区间重叠时判定为冲突。
- */
-export function isScheduleConflict(
-  a: { day: string; start: string; end: string },
-  b: { day: string; start: string; end: string }
-): boolean {
-  if (normalizeDay(a.day) !== normalizeDay(b.day)) return false
-  return a.start < b.end && b.start < a.end
-}
-
 /**
  * 检测学生选课时间冲突（P2 建议：选课时间冲突检测）。
  * 查询学生已选/已录取的课程，与新课程 schedule 比对。
+ *
+ * A-02 修复：时间段解析与冲突判定纯函数已抽离至 lib/schedule-conflict.ts，
+ * 本函数仅保留 DB 查询（读取新课程 schedule + 学生已选课程 schedule）。
  */
 async function checkScheduleConflict(
   tx: Parameters<Parameters<typeof db.transaction>[0]>[0],
@@ -162,12 +90,8 @@ async function checkScheduleConflict(
 
   for (const row of existingCourses) {
     const existingSlots = parseSchedule(row.schedule)
-    for (const newSlot of newSlots) {
-      for (const existingSlot of existingSlots) {
-        if (isScheduleConflict(newSlot, existingSlot)) {
-          return true
-        }
-      }
+    if (hasAnyScheduleConflict(newSlots, existingSlots)) {
+      return true
     }
   }
   return false
@@ -247,24 +171,10 @@ export async function runLottery(courseId: string): Promise<{
     return { enrolled: 0, waitlist: 0 }
   }
 
-  // Fisher-Yates shuffle: 无偏均匀随机排列，避免 sort(() => Math.random() - 0.5) 的分布偏差
-  const shuffled = [...selections]
-  for (let i = shuffled.length - 1; i > 0; i--) {
-    const j = Math.floor(Math.random() * (i + 1))
-    ;[shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]]
-  }
+  // A-02 修复：洗牌 + 分桶算法已抽离至 lib/lottery.ts（partitionLottery）
   const capacity = course.capacity
   const now = new Date()
-
-  const enrolledIds: string[] = []
-  const waitlistIds: string[] = []
-  for (let i = 0; i < shuffled.length; i++) {
-    if (i < capacity) {
-      enrolledIds.push(shuffled[i].id)
-    } else {
-      waitlistIds.push(shuffled[i].id)
-    }
-  }
+  const { enrolledIds, waitlistIds } = partitionLottery(selections, capacity)
 
   const enrolledCount = enrolledIds.length
   const waitlistCount = waitlistIds.length
diff --git a/src/modules/elective/data-access-selections.ts b/src/modules/elective/data-access-selections.ts
index 698c368..ab0b25c 100644
--- a/src/modules/elective/data-access-selections.ts
+++ b/src/modules/elective/data-access-selections.ts
@@ -8,6 +8,7 @@ import {
   electiveCourses,
 } from "@/shared/db/schema"
 import { cacheFn } from "@/shared/lib/cache"
+import { serializeDate as toIso, serializeDateRequired as toIsoRequired } from "@/shared/lib/date-utils"
 
 import {
   buildCourseSelect,
@@ -40,11 +41,6 @@ type SelectionCoreRow = {
   dropReason: string | null
 }
 
-const toIso = (d: Date | null | undefined): string | null =>
-  d ? d.toISOString() : null
-
-const toIsoRequired = (d: Date): string => d.toISOString()
-
 const mapSelectionRow = (
   r: SelectionCoreRow,
   studentNames: Map<string, string | null>
diff --git a/src/modules/elective/data-access.ts b/src/modules/elective/data-access.ts
index eb9e775..f18a7a9 100644
--- a/src/modules/elective/data-access.ts
+++ b/src/modules/elective/data-access.ts
@@ -7,6 +7,7 @@ import { db } from "@/shared/db"
 import { electiveCourses } from "@/shared/db/schema"
 import type { DataScope } from "@/shared/types/permissions"
 import { safeParseDate } from "@/shared/lib/action-utils"
+import { serializeDate as toIso, serializeDateRequired as toIsoRequired } from "@/shared/lib/date-utils"
 import { cacheFn } from "@/shared/lib/cache"
 
 import type {
@@ -19,11 +20,6 @@ import type {
 } from "./schema"
 import { getCourseDisplayResolver } from "./resolvers"
 
-const toIso = (d: Date | null | undefined): string | null =>
-  d ? d.toISOString() : null
-
-const toIsoRequired = (d: Date): string => d.toISOString()
-
 const buildScopeFilter = (scope: DataScope, userId?: string): SQL | null => {
   if (scope.type === "all") return null
   if (scope.type === "owned" && userId) return eq(electiveCourses.teacherId, userId)
diff --git a/src/modules/error-book/components/add-error-book-dialog.tsx b/src/modules/error-book/components/add-error-book-dialog.tsx
index 4bc9719..044482a 100644
--- a/src/modules/error-book/components/add-error-book-dialog.tsx
+++ b/src/modules/error-book/components/add-error-book-dialog.tsx
@@ -2,7 +2,7 @@
 
 import { useState, useTransition, useEffect } from "react"
 import { Plus } from "lucide-react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useTranslations } from "next-intl"
 
 import {
@@ -71,7 +71,7 @@ export function AddErrorBookDialog({
 
   function handleSubmit() {
     if (!questionId) {
-      toast.error(t("messages.selectQuestion"))
+      notify.error(t("messages.selectQuestion"))
       return
     }
     startTransition(async () => {
@@ -82,13 +82,13 @@ export function AddErrorBookDialog({
       )
       const res = await createErrorBookItemAction(undefined, formData)
       if (res.success) {
-        toast.success(res.message ?? t("messages.addedShort"))
+        notify.success(res.message ?? t("messages.addedShort"))
         setOpen(false)
         setQuestionId("")
         setNote("")
         setErrorTags([])
       } else {
-        toast.error(res.message ?? t("messages.addFailed"))
+        notify.error(res.message ?? t("messages.addFailed"))
       }
     })
   }
diff --git a/src/modules/error-book/components/error-book-detail-dialog.tsx b/src/modules/error-book/components/error-book-detail-dialog.tsx
index 5ab94a8..d846e06 100644
--- a/src/modules/error-book/components/error-book-detail-dialog.tsx
+++ b/src/modules/error-book/components/error-book-detail-dialog.tsx
@@ -3,7 +3,7 @@
 import { useState, useTransition } from "react"
 import { useTranslations } from "next-intl"
 import { Archive, Trash2, FileText, Calendar, History, Target } from "lucide-react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 
 import {
   Dialog,
@@ -71,9 +71,9 @@ export function ErrorBookDetailDialog({
       )
       const res = await updateErrorBookNoteAction(undefined, formData)
       if (res.success) {
-        toast.success(t("messages.noteSaved"))
+        notify.success(t("messages.noteSaved"))
       } else {
-        toast.error(res.message ?? t("messages.saveFailed"))
+        notify.error(res.message ?? t("messages.saveFailed"))
       }
     })
   }
@@ -84,10 +84,10 @@ export function ErrorBookDetailDialog({
       formData.append("itemId", item.id)
       const res = await archiveErrorBookItemAction(undefined, formData)
       if (res.success) {
-        toast.success(t("messages.archived"))
+        notify.success(t("messages.archived"))
         setOpen(false)
       } else {
-        toast.error(res.message ?? t("messages.archiveFailed"))
+        notify.error(res.message ?? t("messages.archiveFailed"))
       }
     })
   }
@@ -98,10 +98,10 @@ export function ErrorBookDetailDialog({
       formData.append("itemId", item.id)
       const res = await deleteErrorBookItemAction(undefined, formData)
       if (res.success) {
-        toast.success(t("messages.deleted"))
+        notify.success(t("messages.deleted"))
         setOpen(false)
       } else {
-        toast.error(res.message ?? t("messages.deleteFailed"))
+        notify.error(res.message ?? t("messages.deleteFailed"))
       }
     })
   }
diff --git a/src/modules/error-book/components/review-buttons.tsx b/src/modules/error-book/components/review-buttons.tsx
index 5d10fbb..d3cf479 100644
--- a/src/modules/error-book/components/review-buttons.tsx
+++ b/src/modules/error-book/components/review-buttons.tsx
@@ -2,7 +2,7 @@
 
 import { useState, useTransition } from "react"
 import { RotateCcw, ThumbsUp, Check, Zap } from "lucide-react"
-import { toast } from "sonner"
+import { notify } from "@/shared/lib/notify"
 import { useTranslations } from "next-intl"
 
 import { Button } from "@/shared/components/ui/button"
@@ -65,10 +65,10 @@ export function ReviewButtons({ itemId, onReviewed }: ReviewButtonsProps) {
       formData.append("json", JSON.stringify({ itemId, result }))
       const res = await reviewErrorBookItemAction(undefined, formData)
       if (res.success) {
-        toast.success(res.message ?? t("messages.reviewRecorded"))
+        notify.success(res.message ?? t("messages.reviewRecorded"))
         onReviewed?.()
       } else {
-        toast.error(res.message ?? t("messages.recordFailed"))
+        notify.error(res.message ?? t("messages.recordFailed"))
         setSelected(null)
       }
     })