fix: 3 correctness bugs from codebase audit round 2

- executor.py: clear min_quality_score_for_slot alongside effective_count
  restore in for/else block; leaving the stale floor from the deleted
  file's score blocked the next candidate from filling the restored slot
- cli.py: guard merge_ids with p.get('id') is not None, consistent with
  the _smaller_duplicate_ids fix; bare p['id'] raised KeyError on any
  person dict missing the id field in the auto-merge path
- immich_api.py: replace bare data['major'/'minor'/'patch'] subscripts
  with .get() in get_immich_version; KeyError was silently swallowed by
  except Exception, causing version-gated flags to disable without warning

winnow/executor.py

@@ -612,8 +612,12 @@ def upload_to_frigate(jobs: list[dict]) -> None:
                         # All retries exhausted without a successful upload.
                         # Restore the slot freed by the preceding delete so the next
                         # candidate still sees at_cap=True and must beat the replacement gate.
+                        # Also clear the quality floor — the deleted file's score no longer
+                        # represents any live Frigate file, and leaving it blocks the next
+                        # candidate from filling the restored slot.
                         if at_cap:
                             effective_count += 1
+                            min_quality_score_for_slot = None
 
                     progress.advance(upload_task)