Add GPS service and nautical base city data

- Implement `GpsService` with methods for position updates and enabling/disabling GPS.
- Introduce test data for nautical base cities with key attributes like population, coordinates, and images.
- Update dependencies in `bun.lock` with required packages such as `geojson`.

packages/base-map/package.json

@@ -34,6 +34,7 @@
     "typescript-eslint": "^8.34.1",
     "vite": "^7.0.0",
     "vite-tsconfig-paths": "^5.1.4",
-    "bevy_flurx_api": "^0.1.0"
+    "bevy_flurx_api": "^0.1.0",
+    "geojson": "^0.5.0"
   }
 }