feat: add data sources config system and Earth API integration

- Add data_sources.yaml for configurable data source URLs
- Add data_sources.py to load config with database override support
- Add arcgis_landing_points and arcgis_cable_landing_relation collectors
- Change visualization API to query arcgis_landing_points
- Add /api/v1/datasources/configs/all endpoint
- Update Earth to fetch from API instead of static files
- Fix scheduler collector ID mappings

backend/app/services/collectors/arcgis_cables.py

@@ -9,7 +9,8 @@ from datetime import datetime
 import httpx
 
 from app.services.collectors.base import BaseCollector
-from app.core.config import settings
+from app.core.data_sources import get_data_sources_config
+
 
 
 class ArcGISCableCollector(BaseCollector):
@@ -21,7 +22,12 @@ class ArcGISCableCollector(BaseCollector):
 
     @property
     def base_url(self) -> str:
-        return settings.ARCGIS_CABLE_URL
+        if self._resolved_url:
+            return self._resolved_url
+        from app.core.data_sources import get_data_sources_config
+
+        config = get_data_sources_config()
+        return config.get_yaml_url("arcgis_cables")
 
     async def fetch(self) -> List[Dict[str, Any]]:
         params = {"where": "1=1", "outFields": "*", "returnGeometry": "true", "f": "geojson"}