rebuild(migration): validate local legacy cutover

next/backend/jobs/repository.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import ast
 import json
 import sqlite3
 from datetime import datetime, timedelta
@@ -147,8 +148,28 @@ def public_job(row: sqlite3.Row) -> dict[str, Any]:
     result = dict(row)
     result["source_set"] = json.loads(str(result.pop("source_set_json")))
     result["payload"] = json.loads(str(result.pop("payload_json")))
+    result["error_message"] = _public_error_message(str(result["error_message"]))
     return result
 
 
+def _public_error_message(value: str) -> str:
+    """Normalize AppError tuples written before structured error storage."""
+    if not value.startswith("("):
+        return value
+    try:
+        legacy = ast.literal_eval(value)
+    except (SyntaxError, ValueError):
+        return value
+    if (
+        isinstance(legacy, tuple)
+        and len(legacy) == 3
+        and isinstance(legacy[0], str)
+        and isinstance(legacy[1], str)
+        and isinstance(legacy[2], int)
+    ):
+        return legacy[1]
+    return value
+
+
 def _json(value: Any) -> str:
     return json.dumps(value, ensure_ascii=False, separators=(",", ":"), sort_keys=True)