Enhance country data retrieval and error handling in WatchedMap component

- Improved country code extraction logic to handle null values and prevent rendering errors.
- Added error handling for API responses to ensure graceful degradation in case of failures.
- Updated the logic for determining country codes from GeoJSON features to account for missing values.
- Set default values for watched items and summary to avoid application crashes during data fetch failures.

backend/app/services/sync.py

@@ -218,7 +218,22 @@ async def get_musicbrainz_artist_country(mbid: str) -> Optional[str]:
             )
             if response.status_code == 200:
                 data = response.json()
-                # Check area relations for country
+                
+                # First, check direct country field
+                if "country" in data and data["country"]:
+                    country = data["country"]
+                    if isinstance(country, str) and len(country) == 2:
+                        return country.upper()
+                
+                # Second, check area.iso-3166-1-codes
+                if "area" in data and data["area"]:
+                    area = data["area"]
+                    if "iso-3166-1-codes" in area and area["iso-3166-1-codes"]:
+                        codes = area["iso-3166-1-codes"]
+                        if isinstance(codes, list) and len(codes) > 0:
+                            return codes[0].upper()
+                
+                # Third, check area relations for country
                 if "relations" in data:
                     for relation in data["relations"]:
                         if relation.get("type") == "origin" and "area" in relation: