fix(03): login redirect + API internal URL for Docker networking

- Use window.location.href for full page reload after login (ensures auth state)
- Add API_INTERNAL_URL for server-side requests within Docker network
- Remove unnecessary credentials:'include' from SSR fetch calls
- Update planning state for Phase 03 progress

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

docker-compose.yml

@@ -8,6 +8,8 @@ services:
     environment:
       HOSTNAME: "0.0.0.0"
       NEXT_PUBLIC_API_URL: "http://localhost:3001"
+      API_INTERNAL_URL: "http://api:3001"
+      JWT_SECRET: ${JWT_SECRET:-tessera-dev-jwt-secret-change-in-production}
     networks:
       - frontend-net
       - backend-net