- The <track>'s `error` never reached `onSubTrackError`: it does not bubble, and React 18 attaches no
listener of its own to a <track> (measured in Chrome and jsdom — `onError` 0 calls, `onErrorCapture`
1). Round 1's remount-and-give-up was dead code behind it. The hook now hands the player
`onErrorCapture`, and the test fires a real non-bubbling `error` at a rendered <track>.
- Once reachable, the retry burned its whole budget within milliseconds of an outage (a remount
fetches at once) and the give-up outlived turning subtitles off and on. Retries now wait (2 s,
doubling), running out is reported at once, and picking the track again starts a fresh budget.
- Until the first timeupdate the poll sent `sessionK` — still 0 while the session request was out,
and the PREVIOUS item's start after a move to the next episode. It now sends where the session was
asked to start, and the track choice belongs to the item it was made for, so the next item is not
asked about the old ordinal at the old position.
- A failing poll over a stale `partial` answer was silent: react-query keeps the last good data, the
track stayed "showable", and the notice only rendered for an unmounted track. The hook now decides
what the player says (`subNotice`), independently of whether a window is mounted.
peter
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