Merge exams grading into homework

Redirect /teacher/exams/grading* to /teacher/homework/submissions; remove exam grading UI/actions/data-access; add homework student workflow and update design docs.

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

@@ -0,0 +1,105 @@
+import Link from "next/link"
+
+import { EmptyState } from "@/shared/components/ui/empty-state"
+import { Badge } from "@/shared/components/ui/badge"
+import { Button } from "@/shared/components/ui/button"
+import {
+  Table,
+  TableBody,
+  TableCell,
+  TableHead,
+  TableHeader,
+  TableRow,
+} from "@/shared/components/ui/table"
+import { formatDate } from "@/shared/lib/utils"
+import { getDemoStudentUser, getStudentHomeworkAssignments } from "@/modules/homework/data-access"
+import { Inbox } from "lucide-react"
+
+const getStatusVariant = (status: string): "default" | "secondary" | "outline" => {
+  if (status === "graded") return "default"
+  if (status === "submitted") return "secondary"
+  if (status === "in_progress") return "secondary"
+  return "outline"
+}
+
+const getStatusLabel = (status: string) => {
+  if (status === "graded") return "Graded"
+  if (status === "submitted") return "Submitted"
+  if (status === "in_progress") return "In progress"
+  return "Not started"
+}
+
+export default async function StudentAssignmentsPage() {
+  const student = await getDemoStudentUser()
+
+  if (!student) {
+    return (
+      <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
+        <div className="flex items-center justify-between space-y-2">
+          <div>
+            <h2 className="text-2xl font-bold tracking-tight">Assignments</h2>
+            <p className="text-muted-foreground">Your homework assignments.</p>
+          </div>
+        </div>
+        <EmptyState title="No user found" description="Create a student user to see assignments." icon={Inbox} />
+      </div>
+    )
+  }
+
+  const assignments = await getStudentHomeworkAssignments(student.id)
+  const hasAssignments = assignments.length > 0
+
+  return (
+    <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
+      <div className="flex items-center justify-between space-y-2">
+        <div>
+          <h2 className="text-2xl font-bold tracking-tight">Assignments</h2>
+          <p className="text-muted-foreground">Your homework assignments.</p>
+        </div>
+        <Button asChild variant="outline">
+          <Link href="/student/dashboard">Back</Link>
+        </Button>
+      </div>
+
+      {!hasAssignments ? (
+        <EmptyState title="No assignments" description="You have no assigned homework right now." icon={Inbox} />
+      ) : (
+        <div className="rounded-md border bg-card">
+          <Table>
+            <TableHeader>
+              <TableRow>
+                <TableHead>Title</TableHead>
+                <TableHead>Status</TableHead>
+                <TableHead>Due</TableHead>
+                <TableHead>Attempts</TableHead>
+                <TableHead>Score</TableHead>
+              </TableRow>
+            </TableHeader>
+            <TableBody>
+              {assignments.map((a) => (
+                <TableRow key={a.id}>
+                  <TableCell className="font-medium">
+                    <Link href={`/student/learning/assignments/${a.id}`} className="hover:underline">
+                      {a.title}
+                    </Link>
+                  </TableCell>
+                  <TableCell>
+                    <Badge variant={getStatusVariant(a.progressStatus)} className="capitalize">
+                      {getStatusLabel(a.progressStatus)}
+                    </Badge>
+                  </TableCell>
+                  <TableCell>{a.dueAt ? formatDate(a.dueAt) : "-"}</TableCell>
+                  <TableCell className="tabular-nums text-muted-foreground">
+                    {a.attemptsUsed}/{a.maxAttempts}
+                  </TableCell>
+                  <TableCell className="tabular-nums">{a.latestScore ?? "-"}</TableCell>
+                </TableRow>
+              ))}
+            </TableBody>
+          </Table>
+        </div>
+      )}
+    </div>
+  )
+}
+