Bump version to 1.3.1
- Update manifest description (remove 'Better Deliveroo listings: FSA' prefix)
- Expired FSA cache entries (14d TTL, up from 7d) now return their stale
score so badges never go blank.
- Expired entries are queued for background refresh via the scanner. Null results (no-record vs lookup-failure) are now cached to IDB with appropriate TTLs (14d / 24h).
- Background FSA lookups are concurrency-limited (batches of 5) to avoid rate-limiting.

Also includes: modal/table/filterBar innerHTML→DOM refactors, popup innerHTML cleanup