videos.list (part=snippet) for a single id, including channels the user does
not follow. Data API call (1 quota unit), NOT the rate-limited caption path —
ungated metadata; only the later transcript fetch hits globalFetchGate. Returns
a subscription-less domain.Video scoped to the user, or ErrVideoNotFound for a
deleted/private/typo'd id. Foundation for Feature 2.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
