feat: RFCP MVP deployed on VPS

Iteration 1:
- Dark theme with 3-way toggle
- Dynamic heatmap gradient (blue→red)
- Radius up to 100km
- Save & Calculate workflow

Iteration 2:
- Terrain overlay toggle
- Batch height operations
- Zoom-dependent heatmap rendering

Infrastructure:
- Backend FastAPI on 8888
- Frontend static build via Caddy
- Systemd services
- Caddy reverse proxy integration

backend/venv/lib/python3.12/site-packages/fastapi/openapi/constants.py

@@ -0,0 +1,3 @@
+METHODS_WITH_BODY = {"GET", "HEAD", "POST", "PUT", "DELETE", "PATCH"}
+REF_PREFIX = "#/components/schemas/"
+REF_TEMPLATE = "#/components/schemas/{model}"