feat(v3): restructure project + add complete frontend

- Restructure: move backend from new_project/ to backend/
- Add full React/TypeScript frontend (37 pages, 17 services, 16 type defs, 11 query hooks)
- Add docs/ with SRS specs, user stories, and workflow documentation
- Update .gitignore for new directory layout

Workflows implemented:
  WF1 User Signup, WF2 Placement Test, WF3 Exam Configuration,
  WF4 General English Exam, WF5 Course Generation,
  WF6 Entity Student Onboarding, AI Course Generation,
  Adaptive Learning Engine UI, White-Label Branding, Score Release

Made-with: Cursor

src/pages/teacher/TeacherAssignmentDetail.tsx

@@ -0,0 +1,89 @@
+import { useState } from "react";
+import { useParams, Link } from "react-router-dom";
+import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import { Textarea } from "@/components/ui/textarea";
+import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table";
+import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from "@/components/ui/dialog";
+import { useAssignments } from "@/hooks/queries";
+import { ArrowLeft } from "lucide-react";
+import { useToast } from "@/hooks/use-toast";
+
+export default function TeacherAssignmentDetail() {
+  const { id } = useParams();
+  const { data: assignmentsData, isLoading } = useAssignments();
+  const assignments = assignmentsData?.items ?? [];
+  const submissions: { id: string; assignmentId: string; studentId: string; studentName: string; submittedAt: string; status: string; grade?: number; feedback?: string; file?: string }[] = [];
+  const [gradeOpen, setGradeOpen] = useState(false);
+  const [selectedStudent, setSelectedStudent] = useState<string>("");
+  const { toast } = useToast();
+
+  if (isLoading) return <div className="flex items-center justify-center min-h-[400px]"><div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary" /></div>;
+
+  const assignment = assignments.find(a => String(a.id) === id);
+  const subs = submissions.filter(s => s.assignmentId === id);
+  const maxGrade = 100;
+
+  if (!assignment) return <div className="p-8 text-center text-muted-foreground">Assignment not found.</div>;
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center gap-3">
+        <Button variant="ghost" size="icon" asChild><Link to="/teacher/assignments"><ArrowLeft className="h-4 w-4" /></Link></Button>
+        <div>
+          <h1 className="text-2xl font-bold">{assignment.title}</h1>
+          <p className="text-muted-foreground">{assignment.entity_name} · Due: {assignment.end_date}</p>
+        </div>
+      </div>
+
+      <Card>
+        <CardHeader><CardTitle className="text-lg">Submissions ({subs.length})</CardTitle></CardHeader>
+        <CardContent>
+          <Table>
+            <TableHeader>
+              <TableRow>
+                <TableHead>Student</TableHead>
+                <TableHead>Submitted</TableHead>
+                <TableHead>Status</TableHead>
+                <TableHead>Grade</TableHead>
+                <TableHead></TableHead>
+              </TableRow>
+            </TableHeader>
+            <TableBody>
+              {subs.map(s => (
+                <TableRow key={s.id}>
+                  <TableCell className="font-medium">{s.studentName}</TableCell>
+                  <TableCell className="text-sm">{s.submittedAt}</TableCell>
+                  <TableCell><Badge variant={s.status === "graded" ? "default" : "secondary"} className="capitalize">{s.status}</Badge></TableCell>
+                  <TableCell>{s.grade ?? "—"}</TableCell>
+                  <TableCell>
+                    {s.status === "pending" && (
+                      <Button size="sm" onClick={() => { setSelectedStudent(s.studentName); setGradeOpen(true); }}>Grade</Button>
+                    )}
+                  </TableCell>
+                </TableRow>
+              ))}
+            </TableBody>
+          </Table>
+        </CardContent>
+      </Card>
+
+      <Dialog open={gradeOpen} onOpenChange={setGradeOpen}>
+        <DialogContent>
+          <DialogHeader><DialogTitle>Grade Submission — {selectedStudent}</DialogTitle></DialogHeader>
+          <div className="space-y-4">
+            <div className="space-y-2"><Label>Grade (out of {maxGrade})</Label><Input type="number" placeholder="0" /></div>
+            <div className="space-y-2"><Label>Feedback</Label><Textarea placeholder="Write feedback..." rows={4} /></div>
+          </div>
+          <DialogFooter>
+            <Button variant="outline" onClick={() => setGradeOpen(false)}>Cancel</Button>
+            <Button onClick={() => { setGradeOpen(false); toast({ title: "Grade Saved", description: `${selectedStudent}'s submission has been graded.` }); }}>Save Grade</Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+    </div>
+  );
+}