fix: audit hardening — input validation, error handling, and robustness (#25)

* fix: audit hardening — input validation, error handling, and robustness

- immich_api: guard person["id"] with .get() + early return on missing field
- immich_api: include page number in pagination exception log
- immich_api: validate faces response is a list before indexing
- executor: wrap Image.open() in try/except for non-image HTTP responses
- executor: strip leading 'v' from Frigate version before parsing (v0.16.0 was misread)
- config: wrap FRIGATE_SCORE_CEILING float() parse in try/except with warning
- config: warn when both DATA_DIR and legacy CWD config files exist simultaneously
- scheduler: wrap PID file write in try/except so /tmp failures don't crash startup
- scheduler: clamp sleep to 60s max to bound recovery time after NTP clock jumps
- frigate_api: log unexpected non-list type in get_frigate_person_files at DEBUG

* fix: LIMIT env var crash and symlink guard on person output dir

- jobs: wrap int(LIMIT) parse in try/except — bad value (e.g. "30.5", "all")
  now logs a warning and falls back to the default instead of crashing
- executor: check for symlink before shutil.rmtree on person_dir — prevents
  following a symlink out of OUTPUT_DIR on a shared volume

* chore: bump version to 0.5.3

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "winnow"
-version = "0.5.2"
+version = "0.5.3"
 description = "Selects diverse, high-quality photos from Immich as training data for Frigate face recognition."
 license = "AGPL-3.0-or-later"
 requires-python = ">=3.13"