feat: initial commit — backend API + student cabinet frontend

- Go backend: auth (JWT), points earn/spend, QR token generation,
  partners, admin grant/stats endpoints with chi router
- Next.js 14 frontend: login, student dashboard, transaction history,
  QR display, partners list
- PostgreSQL migrations (4 tables), Redis cache, Docker Compose
- CORS middleware, role-based route protection, Zustand auth store

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,12 @@
+# Backend
+DATABASE_URL=postgres://dev:dev@localhost:5432/cupoints?sslmode=disable
+DATABASE_TEST_URL=postgres://dev:dev@localhost:5433/cupoints_test?sslmode=disable
+REDIS_URL=redis://localhost:6379
+JWT_SECRET=your-secret-key-minimum-32-characters-here
+JWT_ACCESS_TTL=15m
+JWT_REFRESH_TTL=168h
+PORT=8082
+ENV=development
+
+# Frontend
+NEXT_PUBLIC_API_URL=http://localhost:8082