Whitelist: plates added to /whitelist are silently ignored on
detection — no clip, no frames, no DB entry. Manageable via
/whitelist page or from the event detail page per-event.
Stats: /stats shows all known plates ranked by passage count,
with first/last seen dates and one-click whitelist toggle.
Navigation links added to the index header.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
