feat(map): self-hosted PMTiles map tiles, remove alert toast spam

- Replace OpenStreetMap CDN with self-hosted Protomaps PMTiles
  (Wisconsin + Florida regional extracts, served from nginx)
- Add protomaps-leaflet for vector tile rendering in dark theme
- Update CSP to remove openstreetmap.org, add blob: for vector workers
- Add nginx location block for /tiles/ with byte range support
- Mount tiles directory as volume (not baked into image)
- Remove alert_fired/alert_resolved toast notifications that spammed
  "undefined" at fleet scale — dashboard still updates via query invalidation
- Add *.pmtiles to .gitignore (large binaries)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.override.yml

@@ -135,6 +135,8 @@ services:
     container_name: tod_frontend
     ports:
       - "3000:80"
+    volumes:
+      - ./frontend/public/tiles:/usr/share/nginx/html/tiles:ro
     depends_on:
       - api
     deploy: