feat: migrate prototype to canonical structure

- Move app.py to src/api/main.py (STATIC_DIR from env)
- Move static/ to src/web/
- Update Dockerfile and docker-compose.yml
- Add download_srtm.sh script
- Clean up debug/deploy scripts

Refs: multi-agent F0-3

docker-compose.yml

@@ -9,9 +9,14 @@ services:
       - ./src/web:/app/src/web
     environment:
       - DATABASE_URL=sqlite:///./data/enduro.db
+      - DATA_PATH=/app/data/centralfederal.sqlite
       - TILES_DIR=/app/data/terrain
+      - TERRAIN_DIR=/app/data/terrain
+      - STATIC_DIR=/app/src/web
+      - OSRM_URL=http://172.22.0.1:5559
+      - PORT=5556
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:5556/health"]
+      test: ["CMD", "curl", "-f", "http://localhost:5556/api/health"]
       interval: 30s
       timeout: 5s
       retries: 3