fix: harden extraction batch handling

site/db/connection.py

@@ -345,7 +345,10 @@ def execute_returning(sql, params=None):
         sql = sql[:sql.upper().rfind(" RETURNING ")]
 
     cur = conn.execute(sql, params or [])
-    conn.commit()
+    # The outer transaction owns commit and rollback; committing here would make
+    # its rollback ineffective and could expose only part of a multi-write update.
+    if not getattr(_local, "in_transaction", False):
+        conn.commit()
     rowid = cur.lastrowid
 
     if table and rowid: