Initial commit: API gateway with admin console

- FastAPI async gateway with httpx proxying to multiple upstreams
- SQLite database with SQLAlchemy ORM
- Admin console: manage services, users, API keys, endpoint access
- Per-key, per-endpoint granular access control
- OpenAPI document sync and caching (5-minute TTL)
- Request/response logging with full transaction inspection
- In-memory rate limiting (per-key, fixed-window)
- Tiered log retention (7d payloads, 90d rows, incremental vacuum)
- TLS verification toggle per service (for self-signed certificates)
- Service connectivity validation with automatic endpoint refresh
- Request browser with filters and deep-link inspection
- Docker setup with persistent volume
- Modal forms for create/edit flows

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,11 @@
+.venv/
+__pycache__/
+*.pyc
+gateway.db
+cookies.txt
+.claude/
+.git/
+.gitignore
+docker-compose.yml
+Dockerfile
+README.md