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

frontend/src/hooks/queries/useGradebook.ts

@@ -0,0 +1,52 @@
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { queryKeys } from "./keys";
+import { gradebookService } from "@/services/gradebook.service";
+import type { PaginationParams } from "@/types";
+import type { GradingAssignmentCreateRequest } from "@/types/gradebook";
+
+export function useGradebooks(params?: PaginationParams) {
+  return useQuery({
+    queryKey: queryKeys.gradebooks.list(params),
+    queryFn: () => gradebookService.listGradebooks(params),
+  });
+}
+
+export function useGradebookLines(params?: PaginationParams) {
+  return useQuery({
+    queryKey: queryKeys.gradebookLines.list(params),
+    queryFn: () => gradebookService.listGradebookLines(params),
+  });
+}
+
+export function useGradingAssignments(params?: PaginationParams) {
+  return useQuery({
+    queryKey: queryKeys.gradingAssignments.list(params),
+    queryFn: () => gradebookService.listGradingAssignments(params),
+  });
+}
+
+export function useCreateGradingAssignment() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (data: GradingAssignmentCreateRequest) =>
+      gradebookService.createGradingAssignment(data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: queryKeys.gradingAssignments.all }),
+  });
+}
+
+export function useUpdateGradingAssignment() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ id, data }: { id: number; data: Partial<GradingAssignmentCreateRequest> }) =>
+      gradebookService.updateGradingAssignment(id, data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: queryKeys.gradingAssignments.all }),
+  });
+}
+
+export function useDeleteGradingAssignment() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (id: number) => gradebookService.deleteGradingAssignment(id),
+    onSuccess: () => qc.invalidateQueries({ queryKey: queryKeys.gradingAssignments.all }),
+  });
+}