Prod check reads the page's reports, today's trace steps and DeadAir's events

A seventh check groups the browser's errors and lists play starts and
stalls (ipx::client, #190); the trace check names the steps of an item
list, the feed list, a reap and DeadAir's per-file trace (#187), and says
a trace with no name began in the page (#192), which query.py now labels;
the events list has deadair_done and DeadAir's own lines; and "since the
last deploy" is worked out from the container's start.

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

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

@@ -19,7 +19,12 @@ $Q trace   <trace id>                    # one trace as a tree, with its log lin
 $Q prom    '<PromQL>'          [since]   # Prometheus, now; $range becomes `since`
 ```
 
-`since` is `1h`, `24h`, `7d`. Default to `24h`; widen it to see whether something is new.
+`since` is `30m`, `1h`, `24h`, `7d`. Default to `24h`; widen it to see whether something is new.
+"Since the last deploy" is since the container started:
+
+```sh
+S=$(docker inspect iPX -f '{{.State.StartedAt}}'); echo $(( ($(date +%s) - $(date -d "$S" +%s)) / 60 + 1 ))m
+```
 
 ## What the log carries
 
@@ -42,7 +47,10 @@ Events (`ev`): `feed_start`, `feed_done` (new, downloaded, failed, torrents), `f
 routine), `feed_error` (msg), `feed_moved` (from, to: a permanent redirect followed, the address
 updated), `download_done` (bytes), `download_error` (msg, url),
 `torrent_deferred`, `reaped`, `scan_done` (feeds checked), `reap_done`, `status` (feeds, pending,
-downloaded: the healthcheck's, every 30s), `error` (msg).
+downloaded: the healthcheck's, every 30s), `deadair_done` (feed, enclosure, `saved_s` at the
+default pause), `error` (msg). DeadAir also logs `DeadAir found the silences` (`cuts`, `saved_s`,
+`took_ms`) under `ipx::deadair`, and warns `DeadAir could not read a file` when ffmpeg fails on
+one, which it then passes over until the next restart.
 
 `error.type` is the HTTP status (`404`, `503`) or one of `dns`, `redirect_loop`, `timeout`, `tls`,
 `not_a_feed`, `site_message`, `connect`, `parse`, `other`; Loki's `| json` names it `error_type`.
@@ -133,6 +141,16 @@ a count says something happened, the lines and traces say why.
    A web request over a second is worth a look; the trace shows whether the time is in the
    handler or a scan it waited on.
 
+   Steps are `step` spans named by `of` (#187): an item list's `entries_in`, `sanitize`,
+   `deadair`, `count_in`; the feed list's `catalogue`, `feed_list` and its queries; a `reap`'s
+   `missing_files`, `prune_abandoned_failures`, `reap_candidates`, `clean_directory` (once a day
+   since #193, so a reap is about a second), `trim_artwork`, with what it removed on the `reap`
+   span. DeadAir's work on a file is a `deadair` trace (feed, enclosure, cuts) with `probe`,
+   `silencedetect`, `frame_bytes`, `store_plans`: seconds each, more is a file ffmpeg struggles
+   with. A trace with no name in `$Q traces` started in the page (#190, #192): its root is the tap
+   in the browser, which sends no span, so it holds the requests that tap made (API calls, the
+   playlist and audio of a play, position saves, the page's own report) side by side.
+
 6. **The daemon's state, from Prometheus.** Pressure and leaks that requests and traces only
    hint at.
    ```
@@ -168,6 +186,17 @@ a count says something happened, the lines and traces say why.
    the pool's max mean the pool is what they wait on. Live updates missed mean a page showed stale
    counts until reloaded. DeadAir over a minute on one file is a file ffmpeg chokes on.
 
+7. **What the page saw.** The browser's own errors and timings, which no server line shows.
+   ```
+   $Q metric 'sum by (ev, msg) (count_over_time({container="iPX"} |= "\"target\":\"ipx::client\"" | json | __error__="" | level="WARN" [$range]))' 7d
+   $Q logs '{container="iPX"} |= "\"target\":\"ipx::client\"" | json | ev=~"play_start|stall" | line_format "{{.timestamp}} {{.user}} {{.ev}} {{.ms}}ms deadair={{.deadair}} {{.feed}}"' 24h
+   ```
+   A `player_error` is playback that failed in front of someone: `hls.js: ...` is DeadAir's
+   playlist (its trace has the playlist and audio requests), `media error 4` a file the browser
+   cannot play. A `page_error` or `rejection` is a bug in the page; `src` and `line` point into
+   the minified `app.js`, so match the message to `web/src`. `play_start` over 2000 ms, or a
+   `stall`, is worth a trace: was it the server, Cloudflare, or the network.
+
 Also check the container itself, since Loki cannot see a daemon that is not running:
 
 ```sh