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/hooks/queries/useUsers.ts

@@ -0,0 +1,18 @@
+import { useQuery } from "@tanstack/react-query";
+import { queryKeys } from "./keys";
+import { usersService, type UserListParams } from "@/services/users.service";
+
+export function useUsers(params: UserListParams) {
+  return useQuery({
+    queryKey: queryKeys.users.list(params),
+    queryFn: () => usersService.list(params),
+  });
+}
+
+export function useUser(id: number) {
+  return useQuery({
+    queryKey: queryKeys.users.detail(id),
+    queryFn: () => usersService.getById(id),
+    enabled: !!id,
+  });
+}