feat(dashboard): optimize teacher dashboard ui and layout

- Refactor layout: move Needs Grading to main column, Homework to sidebar
- Enhance TeacherStats: replace static counts with actionable metrics (Needs Grading, Active Assignments, Avg Score, Submission Rate)
- Update RecentSubmissions: table view with quick grade actions and late status
- Update TeacherSchedule: vertical timeline view with scroll hints
- Update TeacherHomeworkCard: compact list view
- Integrate Recharts: add TeacherGradeTrends chart and shared chart component
- Update documentation

src/app/(dashboard)/teacher/dashboard/page.tsx

@@ -1,17 +1,25 @@
 import { TeacherDashboardView } from "@/modules/dashboard/components/teacher-dashboard/teacher-dashboard-view"
 import { getClassSchedule, getTeacherClasses, getTeacherIdForMutations } from "@/modules/classes/data-access";
-import { getHomeworkAssignments, getHomeworkSubmissions } from "@/modules/homework/data-access";
+import { getHomeworkAssignments, getHomeworkSubmissions, getTeacherGradeTrends } from "@/modules/homework/data-access";
+import { db } from "@/shared/db";
+import { users } from "@/shared/db/schema";
+import { eq } from "drizzle-orm";
 
 export const dynamic = "force-dynamic";
 
 export default async function TeacherDashboardPage() {
   const teacherId = await getTeacherIdForMutations();
 
-  const [classes, schedule, assignments, submissions] = await Promise.all([
+  const [classes, schedule, assignments, submissions, teacherProfile, gradeTrends] = await Promise.all([
     getTeacherClasses({ teacherId }),
     getClassSchedule({ teacherId }),
     getHomeworkAssignments({ creatorId: teacherId }),
     getHomeworkSubmissions({ creatorId: teacherId }),
+    db.query.users.findFirst({
+      where: eq(users.id, teacherId),
+      columns: { name: true },
+    }),
+    getTeacherGradeTrends(teacherId),
   ]);
 
   return (
@@ -21,6 +29,8 @@ export default async function TeacherDashboardPage() {
         schedule,
         assignments,
         submissions,
+        teacherName: teacherProfile?.name ?? "Teacher",
+        gradeTrends,
       }}
     />
   )