fix: address 10 code review findings (round 3)

- diversity: scale face bbox to thumbnail space before quality check so
  check_face_size uses actual thumbnail pixels, not original-image coords
- diversity: skip asset when face bbox exists but crop guard rejects it,
  preventing InsightFace from picking the wrong person in a group photo
- diversity: add _scale_bbox_to_thumbnail helper (extracted from crop logic)
- diversity: use set for medoid membership test in _kmedoids (O(n) not O(n*k))
- diversity: remove dead np.unique in _select_time_spread (linspace produces
  strictly increasing indices; unique is a no-op and implies wrong semantics)
- embeddings: move os.open/os.dup calls inside try in _suppress_output so
  EMFILE during setup does not leak already-allocated fds
- immich_api: count and log assets with missing/unparseable fileCreatedAt in
  filter_recent_assets instead of silently discarding them
- executor: capture pre_run_count before stale-mapping cleanup so the
  "first run" coaching message doesn't fire after manual file deletion
- cli: use p['id'] (KeyError-safe) instead of p.get('id') in fallback path
  to match all other access sites on the same people list
- cache: narrow except to (OSError, ValueError) in EmbeddingCache.get so
  MemoryError propagates instead of converting OOM to a silent cache miss

winnow/executor.py

@@ -327,6 +327,7 @@ def upload_to_frigate(jobs: list[dict]) -> None:
             # TODO(frigate-api): if Frigate exposes per-file embeddings, compute
             # diversity against the full training set (tracked + manual) rather than
             # relying solely on the Frigate score as a proxy signal.
+            pre_run_count = get_tracked_frigate_file_count(name)
             _snapshot = (
                 all_frigate_files.get(name, []) if all_frigate_files is not None
                 else get_frigate_person_files(name)
@@ -358,7 +359,6 @@ def upload_to_frigate(jobs: list[dict]) -> None:
                         " (file(s) no longer in Frigate)[/dim]"
                     )
             effective_count = get_tracked_frigate_file_count(name)
-            pre_run_count = effective_count
             quality_replacement = job.get("config", {}).get("quality_replacement", False)
             if Config.ENABLE_FRIGATE_SCORES and pre_run_count == 0:
                 progress.console.print(