The page reports its errors and playback timings, and its requests carry a trace (#190)

Nothing the page did in the browser reached the logs: a DeadAir playback
failure on the phone was a toast and nothing more. POST /api/client takes
page errors, unhandled rejections, hls.js and media errors, the time from
play to sound and the length of a stall, and logs them as ev lines under
ipx::client, inside the request's span. Only those kinds are taken, the
text cut to 500 characters, and the page sends each at most once a minute.

The page's API requests send traceparent, a new trace id for each tap or
key, and the server's request span takes it as its parent, so one action's
requests are one trace in Tempo, the report included. The stub DOM the
smoke and native-bridge tests run in gains crypto and performance, which
every browser the page runs in has.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.claude/skills/ipx-prod-check/SKILL.md

@@ -35,6 +35,7 @@ lines had no trace id, the access log's time was `ms`, and each event was logged
 | `ipx::scan` | `ev` and the event's own: `feed`, `new`, `downloaded`, `failed`, `bytes`, `msg`, `url`, `feeds`, `reason`, `from`, `to`; on a failure `error.type` and, from an HTTP error, `http.response.status_code` | the daemon's events, one line each, in words; warnings are feed and download failures |
 | `ipx::io` | `ev`, `feeds`, `pending`, `downloaded` on the `status` reply | commands arriving (`-> {...}`) and the healthcheck's answer |
 | `ipx` | message, sometimes fields | start-up, shutdown, account and config messages |
+| `ipx::client` | `ev`, `user`, `feed`, `enclosure`, `deadair`; `msg`, `src`, `line` on an error; `ms` on a timing | what the page reports from the browser (#190): `page_error`, `rejection` and `player_error` as warnings; `play_start` (ms from play to sound) and `stall` (ms waiting mid-play) as info. Lines carry the trace of the action in the page: its API requests send `traceparent`, one trace id per tap or key |
 
 Events (`ev`): `feed_start`, `feed_done` (new, downloaded, failed, torrents), `feed_skip` (not due,
 routine), `feed_error` (msg), `feed_moved` (from, to: a permanent redirect followed, the address