- Every state and Watch-later write goes through features/video/videoWrites,
which marks the never-refetched lists (related lists, live searches) once
the server has it; a contract test holds it. The Notification Center's
undo, the feed's reset and the Watch-later toggles skipped it before.
- Confirmed marks are also kept apart (qk.videoMarks) and laid over the
related rows: a Show more page landing later rebuilt them from the pages
it read when it started, and dropped a mark made meanwhile.
- Restart on a related video starts at 0 (the session's stored position
won before), and on the one already playing it seeks.
- The watched toggle remembers each video's mark: Back showed the opened
video's launch-time state after a related one was marked.
- The help sheet leaves out the player's keys while a layer above it has
them waiting.
- After a refusal a retry cannot answer, neither Show more (related) nor
Load more (live search) is offered; a failed live-search page keeps the
results already read and says why under them.
- The related cap message counts requests, as the cap does.