feat: add complete EnCoach frontend application

Full React 18 + TypeScript + Vite frontend with:
- 90+ pages (admin, student, teacher, public)
- shadcn/ui component library with 50+ components
- JWT authentication with role-based access control
- TanStack React Query for server state management
- 30+ API service modules
- AI-powered features (coaching, grading, generation)
- Adaptive learning UI (diagnostics, proficiency, plans)
- Institutional LMS management (courses, batches, timetable)
- Communication suite (discussions, announcements, DMs)
- Full CRUD with validation and confirmation dialogs

Made-with: Cursor

public/robots.txt

@@ -0,0 +1,14 @@
+User-agent: Googlebot
+Allow: /
+
+User-agent: Bingbot
+Allow: /
+
+User-agent: Twitterbot
+Allow: /
+
+User-agent: facebookexternalhit
+Allow: /
+
+User-agent: *
+Allow: /