The delta model was only covered at module level; the popup wiring around
it was not exercised at all. Seven specs now drive the real settings UI in
the packed extension, including the migration path: a pre-v3.1.0 snapshot
is converted on open, the legacy key is removed, and a default missing
from that snapshot is delivered again.
Also from the audit pass:
- await the blacklist read in init instead of firing a floating promise
- unify the debug report on the finder's own candidate list, which the
separate traversal missed shadow-DOM videos from
- assert that a single candidate is always returned regardless of its
ranking signals, so no scoring signal can regress a single-player site
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>