FaceID 5.3: safe enrollment and reliable Frigate evidence

[r11a]

What changed

• prevents silent enrollment of the wrong person from group photos and adds an explicit visual face picker when gallery evidence is ambiguous
• distinguishes a Frigate clip that is still unavailable from a readable clip with no usable face, with configurable durable retries
• uses the configured Frigate recording API for selected high-resolution cameras without exposing go2rtc port 1984
• adds stale-release-tag protection and bumps the add-on, backend and UI to 5.3.0

Why

The previous upload path could poison a person's gallery by choosing the largest bystander. The clip path also marked a not-yet-finalized recording as successfully analyzed, permanently losing evidence that appeared seconds later.

Validation

• python -m compileall -q app
• python -m unittest discover -s tests -v — 65 passed, one optional sklearn test skipped
• JavaScript parsed with node --check
• manifest YAML, import smoke test and add-on source synchronization verified