test(v2-ingestion): harden public-source schema contract and docs

apps/ingestion/extractors/bcl.py

@@ -16,6 +16,16 @@ def _first_non_empty(record: dict[str, Any], *keys: str) -> Any:
     return None
 
 
+def _first_non_empty_text(record: dict[str, Any], *keys: str) -> str | None:
+    for key in keys:
+        value = record.get(key)
+        if isinstance(value, str):
+            stripped = value.strip()
+            if stripped:
+                return stripped
+    return None
+
+
 ESSENTIAL_FIELDS = {
     "competition_external_id",
     "competition_name",
@@ -108,7 +118,9 @@ class BCLSnapshotExtractor(BaseSnapshotExtractor):
         team_external_id = _first_non_empty(source_record, "team_external_id", "team_id") or _first_non_empty(
             team_obj, "id", "team_id"
         )
-        team_name = _first_non_empty(source_record, "team_name", "team") or _first_non_empty(team_obj, "name")
+        team_name = _first_non_empty_text(source_record, "team_name", "team") or _first_non_empty_text(
+            team_obj, "name"
+        )
 
         normalized = {
             "competition_external_id": self.competition_external_id,