fixed a bug

sentence_api/repository.py

@@ -244,7 +244,24 @@ class VideoRepository:
             )
 
     def mark_processing(self, video_hash: str) -> None:
-        self._update_status(video_hash, "processing", None)
+        normalized_hash = normalize_video_hash(video_hash)
+        with self._connect() as connection:
+            connection.execute(
+                "DELETE FROM sentences WHERE video_hash = ?",
+                (normalized_hash,),
+            )
+            connection.execute(
+                "DELETE FROM moss_segments WHERE video_hash = ?",
+                (normalized_hash,),
+            )
+            connection.execute(
+                """
+                UPDATE videos
+                SET status = ?, error_message = NULL, transcription = NULL, updated_at = ?
+                WHERE video_hash = ?
+                """,
+                ("processing", utc_now(), normalized_hash),
+            )
 
     def mark_failed(self, video_hash: str, message: str) -> None:
         self._update_status(video_hash, "failed", message[:4000])