After a page reload the in-memory caches (service fingerprintCache and the
client watch-history cache) are empty, so loadLatest's non-blocking path returned
[] and the For You feed suppressed nothing until the slow background network
refresh (~150 encrypted chunk events over 2 sequential relay round-trips) landed.
Return the best available items immediately via getCachedSnapshotItems, which
falls back to the persisted localStorage snapshot. Reloads now suppress watched
videos right away using the last-known history, while the background refresh
still runs and corrects it (firing "fingerprint" to re-run the feed). Persisted
items were previously valid, so there is no correctness risk.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
