fix: embedding cache key mismatch, scheduler path/exception, log handler leak

embeddings.py: face embedding cache used 'immich' for lookup but
'insightface' for storage, so the cache was never hit for locally-
computed embeddings. Unified to 'insightface'/'siglip' throughout.
This affects all users since ENABLE_CACHE now defaults to true.

scheduler.py: INSIGHTFACE_HOME=/models/.insightface was having
'.insightface' appended again, making buffalo_l check always report
'will download'. Also catch BaseException (not just Exception) so a
SystemExit from a library call can't silently kill all future runs.

log_config.py: handlers.clear() abandoned open FileHandler fds on
each scheduled main() call. Close each handler properly before removal.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

winnow/log_config.py

@@ -26,10 +26,12 @@ def setup_logging(verbose: bool = False) -> logging.Logger:
     """Configure logging with Rich console and file output."""
     level = logging.DEBUG if verbose else logging.INFO
 
-    # Configure root logger
+    # Configure root logger; close existing handlers before replacing them
     root = logging.getLogger()
     root.setLevel(level)
-    root.handlers.clear()
+    for h in root.handlers[:]:
+        h.close()
+        root.removeHandler(h)
 
     # Rich console handler - uses shared console to avoid breaking progress bars
     root.addHandler(RichHandler(rich_tracebacks=True, markup=True, console=console))