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/useSignup.ts

@@ -0,0 +1,41 @@
+import { useQuery, useMutation } from "@tanstack/react-query";
+import { queryKeys } from "./keys";
+import { signupService } from "@/services/signup.service";
+import type { RegisterRequest, VerifyEmailRequest, OnboardingData } from "@/types";
+
+export function useGoals() {
+  return useQuery({
+    queryKey: queryKeys.signup.goals,
+    queryFn: signupService.getGoals,
+  });
+}
+
+export function useRegister() {
+  return useMutation({
+    mutationFn: (data: RegisterRequest) => signupService.register(data),
+  });
+}
+
+export function useVerifyEmail() {
+  return useMutation({
+    mutationFn: (data: VerifyEmailRequest) => signupService.verifyEmail(data),
+  });
+}
+
+export function useResendOtp() {
+  return useMutation({
+    mutationFn: (email: string) => signupService.resendOtp({ email }),
+  });
+}
+
+export function useCheckEmail() {
+  return useMutation({
+    mutationFn: (email: string) => signupService.checkEmail(email),
+  });
+}
+
+export function useCompleteOnboarding() {
+  return useMutation({
+    mutationFn: (data: OnboardingData) => signupService.completeOnboarding(data),
+  });
+}