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/base.py

@@ -23,6 +23,13 @@ class BaseCollector(ABC):
         self._current_task = None
         self._db_session = None
         self._datasource_id = 1
+        self._resolved_url: Optional[str] = None
+
+    async def resolve_url(self, db: AsyncSession) -> None:
+        from app.core.data_sources import get_data_sources_config
+
+        config = get_data_sources_config()
+        self._resolved_url = await config.get_url(self.name, db)
 
     def update_progress(self, records_processed: int):
         """Update task progress - call this during data processing"""
@@ -65,6 +72,8 @@ class BaseCollector(ABC):
         self._current_task = task
         self._db_session = db
 
+        await self.resolve_url(db)
+
         try:
             raw_data = await self.fetch()
             task.total_records = len(raw_data)
@@ -87,7 +96,6 @@ class BaseCollector(ABC):
                 "execution_time_seconds": (datetime.utcnow() - start_time).total_seconds(),
             }
         except Exception as e:
-            # Log task failure
             task.status = "failed"
             task.error_message = str(e)
             task.completed_at = datetime.utcnow()