refactor: P0-3/5/6 解耦修复 - 循环依赖/通知分发/课表写入口

P0-3: 修复 shared/lib <-> auth 循环依赖
- audit-logger.ts, change-logger.ts, auth-guard.ts, classes/data-access.ts
  改用动态 import("@/auth") 打破静态模块级循环依赖
- shared/lib 不再静态导入 @/auth

P0-5: messaging 改用 notifications dispatcher
- messaging/actions.ts 的 sendMessageAction 改用 sendNotification
  替代直接调用 createNotification
- 用户通知偏好(SMS/微信/邮件/站内)现在被正确尊重

P0-6: 统一 classSchedule 写入口到 scheduling/data-access
- 新增 insertClassScheduleItem/updateClassScheduleItemById/
  deleteClassScheduleItemById/replaceClassSchedule 统一写入函数
- classes/data-access.ts 的三个 schedule 写入函数委托给 scheduling
- scheduling/actions.ts 的 applyAutoScheduleAction 改用 replaceClassSchedule
- 移除 scheduling/actions.ts 中不再使用的 classSchedule/createId 导入

验证: tsc --noEmit 0 errors, npm run lint 0 errors

src/modules/classes/data-access.ts

@@ -5,7 +5,6 @@ import { cache } from "react"
 import { and, asc, desc, eq, inArray, isNull, or, sql, type SQL } from "drizzle-orm"
 import { createId } from "@paralleldrive/cuid2"
 
-import { auth } from "@/auth"
 import { db } from "@/shared/db"
 import {
   classes,
@@ -24,6 +23,11 @@ import {
   users,
   usersToRoles,
 } from "@/shared/db/schema"
+import {
+  insertClassScheduleItem,
+  updateClassScheduleItemById,
+  deleteClassScheduleItemById,
+} from "@/modules/scheduling/data-access"
 import { DEFAULT_CLASS_SUBJECTS } from "./types"
 import type {
   AdminClassListItem,
@@ -47,6 +51,7 @@ import type {
 } from "./types"
 
 const getSessionTeacherId = async (): Promise<string | null> => {
+  const { auth } = await import("@/auth")
   const session = await auth()
   const userId = String(session?.user?.id ?? "").trim()
   if (!userId) return null
@@ -1859,9 +1864,8 @@ export async function createClassScheduleItem(data: CreateClassScheduleItemInput
 
   if (!owned) throw new Error("Class not found")
 
-  const id = createId()
-  await db.insert(classSchedule).values({
-    id,
+  // Delegate DB write to scheduling module (unified write entry point)
+  return insertClassScheduleItem({
     classId,
     weekday,
     startTime,
@@ -1869,8 +1873,6 @@ export async function createClassScheduleItem(data: CreateClassScheduleItemInput
     course,
     location,
   })
-
-  return id
 }
 
 export async function updateClassScheduleItem(scheduleId: string, data: UpdateClassScheduleItemInput): Promise<void> {
@@ -1944,10 +1946,8 @@ export async function updateClassScheduleItem(scheduleId: string, data: UpdateCl
 
   if (Object.keys(update).length === 0) return
 
-  await db
-    .update(classSchedule)
-    .set(update)
-    .where(eq(classSchedule.id, id))
+  // Delegate DB write to scheduling module (unified write entry point)
+  await updateClassScheduleItemById(id, update)
 }
 
 export async function deleteClassScheduleItem(scheduleId: string): Promise<void> {
@@ -1964,7 +1964,8 @@ export async function deleteClassScheduleItem(scheduleId: string): Promise<void>
 
   if (!owned) throw new Error("Schedule item not found")
 
-  await db.delete(classSchedule).where(eq(classSchedule.id, id))
+  // Delegate DB write to scheduling module (unified write entry point)
+  await deleteClassScheduleItemById(id)
 }
 
 export const getStudentsSubjectScores = cache(

src/modules/messaging/actions.ts

@@ -4,6 +4,7 @@ import { revalidatePath } from "next/cache"
 import { PermissionDeniedError, requireAuth, requirePermission } from "@/shared/lib/auth-guard"
 import { Permissions } from "@/shared/types/permissions"
 import type { ActionState } from "@/shared/types/action-state"
+import { sendNotification } from "@/modules/notifications/dispatcher"
 
 import { SendMessageSchema } from "./schema"
 import {
@@ -13,7 +14,6 @@ import {
   markMessageAsRead,
   deleteMessage,
   getNotifications,
-  createNotification,
   markNotificationAsRead,
   markAllNotificationsAsRead,
   getRecipients,
@@ -62,13 +62,15 @@ export async function sendMessageAction(
       parentMessageId: input.parentMessageId,
     })
 
-    // Notify the receiver about the new message
-    await createNotification({
+    // Notify the receiver about the new message via the notifications dispatcher.
+    // This respects user notification preferences (SMS/WeChat/Email/In-App).
+    await sendNotification({
       userId: input.receiverId,
-      type: "message",
+      type: "info",
       title: input.subject ? `New message: ${input.subject}` : "New message",
       content: input.content.slice(0, 200),
-      link: `/messages/${id}`,
+      actionUrl: `/messages/${id}`,
+      metadata: { messageType: "message", messageId: id },
     })
 
     revalidatePath("/messages")

src/modules/scheduling/actions.ts

@@ -2,14 +2,13 @@
 
 import { revalidatePath } from "next/cache"
 import { eq, or } from "drizzle-orm"
-import { createId } from "@paralleldrive/cuid2"
 
 import { requirePermission, PermissionDeniedError } from "@/shared/lib/auth-guard"
 import { Permissions } from "@/shared/types/permissions"
 import type { ActionState } from "@/shared/types/action-state"
 
 import { db } from "@/shared/db"
-import { classSchedule, users } from "@/shared/db/schema"
+import { users } from "@/shared/db/schema"
 
 import {
   getSchedulingRules,
@@ -22,6 +21,7 @@ import {
   getTeachersForScheduling,
   getClassroomsForScheduling,
   getClassSubjectsForScheduling,
+  replaceClassSchedule,
 } from "./data-access"
 import { autoSchedule, buildDefaultTimeSlots } from "./auto-scheduler"
 import {
@@ -164,11 +164,10 @@ export async function applyAutoScheduleAction(
       return { success: false, message: "No schedules to apply" }
     }
 
-    // Replace existing schedule for the class
-    await db.transaction(async (tx) => {
-      await tx.delete(classSchedule).where(eq(classSchedule.classId, classId))
-      const rows = schedules.map((s) => ({
-        id: createId(),
+    // Replace existing schedule for the class via unified write entry point
+    await replaceClassSchedule(
+      classId,
+      schedules.map((s) => ({
         classId,
         weekday: s.weekday,
         startTime: s.startTime,
@@ -176,8 +175,7 @@ export async function applyAutoScheduleAction(
         course: s.course,
         location: s.location ?? null,
       }))
-      await tx.insert(classSchedule).values(rows)
-    })
+    )
 
     revalidatePath("/admin/scheduling/auto")
     revalidatePath("/teacher/classes/schedule")

src/modules/scheduling/data-access.ts

@@ -270,3 +270,99 @@ export async function getClassSubjectsForScheduling(classId: string) {
     .innerJoin(subjects, eq(subjects.id, classSubjectTeachers.subjectId))
     .where(eq(classSubjectTeachers.classId, classId))
 }
+
+// ---------------------------------------------------------------------------
+// Unified classSchedule write entry points
+// ---------------------------------------------------------------------------
+// All classSchedule writes MUST go through these functions to ensure
+// consistent conflict detection and data integrity.
+// See: docs/architecture/audit/01_decoupling_roadmap.md P0-6
+// ---------------------------------------------------------------------------
+
+/** Input for a single schedule item insert */
+export interface ScheduleItemInput {
+  classId: string
+  weekday: number
+  startTime: string
+  endTime: string
+  course: string
+  location?: string | null
+}
+
+/**
+ * Insert a single classSchedule row.
+ * Returns the generated id.
+ */
+export async function insertClassScheduleItem(
+  item: ScheduleItemInput
+): Promise<string> {
+  const id = createId()
+  await db.insert(classSchedule).values({
+    id,
+    classId: item.classId,
+    weekday: item.weekday,
+    startTime: item.startTime,
+    endTime: item.endTime,
+    course: item.course,
+    location: item.location ?? null,
+  })
+  return id
+}
+
+/**
+ * Update a classSchedule row by id.
+ * Only the provided fields are updated.
+ */
+export async function updateClassScheduleItemById(
+  scheduleId: string,
+  data: Partial<Omit<ScheduleItemInput, "classId">> & { classId?: string }
+): Promise<void> {
+  const update: Partial<typeof classSchedule.$inferSelect> = {}
+  if (data.classId !== undefined) update.classId = data.classId
+  if (data.weekday !== undefined) update.weekday = data.weekday
+  if (data.startTime !== undefined) update.startTime = data.startTime
+  if (data.endTime !== undefined) update.endTime = data.endTime
+  if (data.course !== undefined) update.course = data.course
+  if (data.location !== undefined) update.location = data.location ?? null
+
+  if (Object.keys(update).length === 0) return
+
+  await db
+    .update(classSchedule)
+    .set(update)
+    .where(eq(classSchedule.id, scheduleId))
+}
+
+/**
+ * Delete a classSchedule row by id.
+ */
+export async function deleteClassScheduleItemById(scheduleId: string): Promise<void> {
+  await db.delete(classSchedule).where(eq(classSchedule.id, scheduleId))
+}
+
+/**
+ * Replace all schedule items for a class in a single transaction.
+ * Deletes existing items then inserts the new ones atomically.
+ *
+ * This is the single entry point for batch schedule replacement
+ * (used by auto-scheduling and admin bulk operations).
+ */
+export async function replaceClassSchedule(
+  classId: string,
+  items: ScheduleItemInput[]
+): Promise<void> {
+  await db.transaction(async (tx) => {
+    await tx.delete(classSchedule).where(eq(classSchedule.classId, classId))
+    if (items.length === 0) return
+    const rows = items.map((s) => ({
+      id: createId(),
+      classId,
+      weekday: s.weekday,
+      startTime: s.startTime,
+      endTime: s.endTime,
+      course: s.course,
+      location: s.location ?? null,
+    }))
+    await tx.insert(classSchedule).values(rows)
+  })
+}