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/Dockerfile

@@ -0,0 +1,16 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+
+# Install dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy app
+COPY app /app/app
+
+# Expose port
+EXPOSE 8000
+
+# Run
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]