fix: address 3 quality review findings — record_frigate_files_batch cache mutation, tracker_ok flag, LIMIT guard

- record_frigate_files_batch: copy-before-mutate so a write failure
  doesn't leave cache ahead of disk (same fix as remove_frigate_files_batch)
- executor: replace tracker_ok boolean with try/else
- jobs: collapse duplicate custom_limit is not None checks into one guard

Bump version to 0.6.3.

winnow/executor.py

@@ -510,7 +510,6 @@ def upload_to_frigate(jobs: list[dict]) -> None:
 
                                 asset_id = asset_map.get(fname)
                                 if asset_id:
-                                    tracker_ok = True
                                     try:
                                         mark_uploaded(
                                             asset_id,
@@ -520,7 +519,6 @@ def upload_to_frigate(jobs: list[dict]) -> None:
                                             frigate_score=pre_fscore,
                                         )
                                     except Exception as tracker_exc:
-                                        tracker_ok = False
                                         # Upload to Frigate succeeded — don't retry on tracker
                                         # failure or we'd upload a duplicate to Frigate.
                                         logger.error(
@@ -528,7 +526,7 @@ def upload_to_frigate(jobs: list[dict]) -> None:
                                             " but asset may be re-selected next run: %s",
                                             fname, tracker_exc,
                                         )
-                                    if tracker_ok:
+                                    else:
                                         if pre_fscore is not None:
                                             person_has_fscores = True
                                         actually_uploaded.append((fname, asset_id))