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

.env.example

@@ -0,0 +1,3 @@
+# Dev: use /api with Vite proxy (see vite.config.ts). Production: full URL, e.g. https://your-odoo/api
+VITE_API_BASE_URL=/api
+VITE_APP_NAME=EnCoach