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/modules/elective/components/elective-filters.tsx

@@ -0,0 +1,49 @@
+"use client"
+
+import { useQueryState, parseAsString } from "nuqs"
+
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/shared/components/ui/select"
+import { FilterBar, FilterSearchInput } from "@/shared/components/ui/filter-bar"
+
+export function ElectiveFilters() {
+  const [search, setSearch] = useQueryState("q", parseAsString.withDefault(""))
+  const [mode, setMode] = useQueryState("mode", parseAsString.withDefault("all"))
+
+  const hasFilters = Boolean(search || mode !== "all")
+
+  return (
+    <FilterBar
+      layout="between"
+      hasFilters={hasFilters}
+      onReset={() => {
+        setSearch(null)
+        setMode(null)
+      }}
+    >
+      <FilterSearchInput
+        value={search}
+        onChange={(v) => setSearch(v || null)}
+        placeholder="Search by course name, teacher..."
+      />
+
+      <div className="flex flex-wrap gap-2 w-full md:w-auto">
+        <Select value={mode} onValueChange={(val) => setMode(val === "all" ? null : val)}>
+          <SelectTrigger className="w-[160px] bg-background border-muted-foreground/20">
+            <SelectValue placeholder="Selection Mode" />
+          </SelectTrigger>
+          <SelectContent>
+            <SelectItem value="all">All Modes</SelectItem>
+            <SelectItem value="fcfs">First Come First Served</SelectItem>
+            <SelectItem value="lottery">Lottery</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+    </FilterBar>
+  )
+}