Add services layer, tests, streaming UI, and cleanup legacy code

crawler/services/district_service.py

@@ -0,0 +1,38 @@
+"""Unified district service - shared between CLI and HTTP API."""
+from rec.districts import get_districts as _get_districts
+
+
+def get_all_districts() -> dict[str, str]:
+    """Get all available districts with their region IDs.
+
+    Used by:
+    - CLI: --district option choices
+    - API: GET /api/get_districts
+
+    Returns:
+        Dictionary mapping district names to region IDs
+    """
+    return _get_districts()
+
+
+def get_district_names() -> list[str]:
+    """Get list of all district names.
+
+    Returns:
+        List of district names
+    """
+    return list(_get_districts().keys())
+
+
+def validate_districts(district_names: list[str]) -> tuple[bool, list[str]]:
+    """Validate that district names exist.
+
+    Args:
+        district_names: List of district names to validate
+
+    Returns:
+        Tuple of (all_valid, invalid_names)
+    """
+    valid_districts = set(_get_districts().keys())
+    invalid = [d for d in district_names if d not in valid_districts]
+    return len(invalid) == 0, invalid