feat(student): 完成 student 模块 v4 剩余修复

- P1-4.2: 新增班级详情页 courses/[classId]，展示教师/学校/教室信息与课表

- P2-2.5: 今日课表卡片高亮当前/下一节课（useMemo 实时计算）

- P2-3.9: 作业作答进度网格支持点击跳转题目（scrollIntoView）

- P2-3.10: 作业复习视图显示正确答案（选择/判断/文本题）

- P2-4.4: 课程列表支持按班级名/教师/学校搜索

- P2-5.2: 成绩页新增趋势折线图组件 GradeTrendCard

- P2-9.2/9.3: 诊断报告新增历史记录卡片与弱点练习入口

- P2-10.2: 选课列表支持搜索与选课模式筛选

- P2-11.3: 修复教材阅读页全屏溢出

- P3-1.5: 面包屑保留首个角色段作为根上下文

- P3-7.3: 课表项支持点击跳转至班级详情页（ScheduleList href）

src/app/(dashboard)/student/learning/courses/page.tsx

@@ -3,15 +3,27 @@ import { UserX } from "lucide-react"
 import { getStudentClasses } from "@/modules/classes/data-access"
 import { getCurrentStudentUser } from "@/modules/users/data-access"
 import { StudentCoursesView } from "@/modules/student/components/student-courses-view"
+import { CourseFilters } from "@/modules/student/components/course-filters"
 import { EmptyState } from "@/shared/components/ui/empty-state"
 
 export const dynamic = "force-dynamic"
 
-export default async function StudentCoursesPage() {
+type SearchParams = { [key: string]: string | string[] | undefined }
+
+const getParam = (params: SearchParams, key: string) => {
+  const v = params[key]
+  return Array.isArray(v) ? v[0] : v
+}
+
+export default async function StudentCoursesPage({
+  searchParams,
+}: {
+  searchParams: Promise<SearchParams>
+}) {
   const student = await getCurrentStudentUser()
   if (!student) {
     return (
-      <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
+      <div className="space-y-8">
         <div>
           <h2 className="text-2xl font-bold tracking-tight">Courses</h2>
           <p className="text-muted-foreground">Your enrolled classes.</p>
@@ -25,16 +37,31 @@ export default async function StudentCoursesPage() {
     )
   }
 
-  const classes = await getStudentClasses(student.id)
+  const [sp, classes] = await Promise.all([
+    searchParams,
+    getStudentClasses(student.id),
+  ])
+
+  const q = (getParam(sp, "q") || "").toLowerCase().trim()
+  const filteredClasses = q
+    ? classes.filter((c) => {
+        return (
+          c.name.toLowerCase().includes(q) ||
+          (c.teacherName?.toLowerCase().includes(q) ?? false) ||
+          (c.schoolName?.toLowerCase().includes(q) ?? false) ||
+          (c.homeroom?.toLowerCase().includes(q) ?? false)
+        )
+      })
+    : classes
 
   return (
-    <div className="flex h-full flex-col space-y-8 p-8">
+    <div className="space-y-8">
       <div>
         <h2 className="text-2xl font-bold tracking-tight">Courses</h2>
         <p className="text-muted-foreground">Your enrolled classes.</p>
       </div>
-      <StudentCoursesView classes={classes} />
+      {classes.length > 0 && <CourseFilters />}
+      <StudentCoursesView classes={filteredClasses} />
     </div>
   )
 }
-