FaceID 5.2.1: bounded review storage and visit-aware presence

[r11a]

What changed

• Bounds the review inbox to representative samples and prunes oversized existing queues on startup.
• Separates confirming an identity from adding gallery training photos.
• Classifies repeated same-camera recognition as a quiet presence update.
• Keeps camera transitions and returns as meaningful visit events.
• Caps audit evidence, decoded frame caches, and optional AI grids.
• Updates the Home Assistant add-on and UI to version 5.2.1.

Why

The review screen could accumulate thousands of redundant crops, and repeated Frigate events for a continuously visible person inflated activity, statistics, automations, and stored evidence.

Impact

Existing event metadata, scores, timestamps, and investigation history remain. On first 5.2.1 startup, redundant temporary crops are removed automatically. HA presence and last-seen continue to refresh, while repeated observations no longer produce duplicate user-facing events.

Validation

• python -m unittest discover -s tests -q — 56 tests passed, 1 optional dependency test skipped.
• Inline UI JavaScript syntax check passed.
• Add-on app/static mirror hash checks passed.
• Manifest, backend and embedded UI version sync test passed.
• Docker image build was not available locally because Docker is not installed.