iOS CarPlay: the phone's bar takes up the car's episode; only playable shows (#442, #443, #444)

#442: a car's pick told the page `replaced`, and the page closed its player bar, so leaving the
car with the episode playing left nothing on the phone to pause it. And when the car launched the
app, the page loaded later and was never told anything played. Now the app sends `nowPlaying`
(the item, its place, playing or not) on a car pick, at the page's `ready`, and on coming
forward, and the page's bar takes it up and drives the phone's player. `replaced` is still
handled for builds before this one.

#443: Shows listed every feed with items, blogs included. Now only feeds with a downloaded file,
and an episode only with a downloaded audio file: /media/{id} answers 404 before the download.

#444: tests/native-bridge.ts read its failure count before the CarPlay checks, so those could
fail and still exit 0. The count is read last now.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RqkrVARreS9wxzH5o2rF7N

ios/README.md

@@ -134,7 +134,8 @@ App to page, as `window.ipxNative.on(...)`:
 | `{t:"push", token, sandbox}` | at `ready` and when Apple gives a new one: the phone's push token, for the page to register with ipx (`POST /api/push/devices`) (#433) |
 | `{t:"sleep", left}` | at `ready`, while the timer runs: seconds left, for a page that reloaded |
 | `{t:"slept"}` | the timer ran out and playback paused |
-| `{t:"replaced"}` | the car chose another episode; the page's player bar closes without saving |
+| `{t:"nowPlaying", feedId, guid, enc, title, feedTitle, artwork, playing, cur, dur}` | what the phone plays that the page did not choose: the car's pick, and at `ready` and on coming forward whatever is loaded; the page's player bar takes it up (#442) |
+| `{t:"replaced"}` | builds before `nowPlaying`: the car chose another episode, and the page's player bar closes without saving |
 
 The app writes the position (every ten seconds and on pause) and marks an item read at 90%, from
 its own clock, so both happen while the page is frozen. Video stays in the page.