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/cache.py

@@ -75,7 +75,7 @@ class EmbeddingCache:
         if os.path.exists(path):
             try:
                 return np.load(path)
-            except Exception:
+            except (OSError, ValueError):
                 return None
         return None