Add a root-level Makefile to manage frontend, backend, and nginx services:
- `make check` validates required dependencies (Node.js 22+, pnpm, uv, nginx)
- `make install` installs all project dependencies
- `make dev` starts all services with unified port 2026
- `make stop` and `make clean` for cleanup
Update nginx configuration:
- Change port from 8000 to 2026
- Add frontend upstream and routing (port 3000)
- Add /api/langgraph/* routing with path rewriting to LangGraph server
- Keep other /api/* routes to Gateway API
- Route non-API requests to frontend
Update frontend configuration:
- Use relative URLs through nginx proxy by default
- Support environment variables for direct backend access
- Construct full URL for LangGraph SDK compatibility
Clean up backend Makefile by removing nginx and serve targets.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
