feat: initial frontend codebase — EnCoach v3

React 18 + TypeScript + Vite 5 + Tailwind CSS + shadcn/ui frontend:
- Multi-role auth: student, teacher, admin, corporate, agent, developer
- Student portal: dashboard, courses, adaptive learning, exams, placement
- Teacher portal: courses, assignments, grading, attendance, AI workbench
- Admin portal: 60+ management pages (LMS, exams, users, entities, AI)
- AI-powered features: study coach, generation page, gap analysis, TTS
- Exam system: session, auto-save, results, grading queue
- Full IELTS workflow: reading/listening/writing/speaking modules

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: /