fix(logs): deep-review round 1 — say each failure once, and scrub it everywhere

- yt-dlp's text is scrubbed wherever it is logged, not only in the adapter:
  `formats.log_safe` takes out the URL, the `[extractor] <id>:` prefix and
  file paths, and the job-failed, refused, edit-failed and backfill lines use
  it. Done lines log the asset id, not the title-built path. The PII contract
  now bans `rel`/`rel_path`/`title`.
- A traceback goes with a download/edit failure only when it is our own code
  failing; for yt-dlp's DownloadError, our RuntimeErrors and OSErrors its foot
  is the unscrubbed message.
- yt-dlp's `error` maps to WARNING: it fires on attempts the fallback client
  set recovers from; the job's verdict is `download.job.failed`.
- The sink groups a bare `%s` pass-through by its text (numbers folded), and
  a process's last batch closes the repeat window, so a short-lived download
  child still reports what it dropped.
- Worker-side failures (stall, wall-clock, no asset, cached asset error) log
  `download.job.failed` with a cause; they left no line at all before. The
  crash, supervisor-error and non-zero-exit lines carry the code too.
- An edit failure is one coded line in `_fail_edit`, for every path.
- `logs.get_logger("__main__")` resolves to the `-m` module, so the worker
  and the download child keep their names.
- TRACE lines carrying user content are gated on `logs.consented_trace()`,
  not on the process level; a contract test pins it.
- The OAuth token refresh goes through `_upstream_failure`; transport errors
  carry reason `transport`. Subscribe recognises a duplicate by reason code
  only (the prose fallback was dead).
- Once-only guards for a stale sysconfig override and a refusing HLS session
  directory; item_detail splits Plex failures from our own parse bugs.
- The playlist breaker line names the playlist and the action; comments that
  were false (runner noqa, `_merge_vtt`, sink grouping) are corrected.

backend/app/sysconfig.py

@@ -20,6 +20,10 @@ log = logs.get_logger(__name__)
 # Config keys whose stored ciphertext failed to decrypt — tracked so the warning is logged once per
 # key, not once per request (bounded by the number of secret config keys).
 _decrypt_warned: set[str] = set()
+# The same for a stored value that no longer coerces (a choice list that shrank in a release): it
+# fails on EVERY read of a hot knob until someone saves it again. Keyed with the value, so saving a
+# different bad value is reported afresh (bounded by the keys times the values ever saved).
+_coerce_warned: set[tuple[str, str]] = set()
 
 
 @dataclass(frozen=True)
@@ -270,12 +274,14 @@ def get(db: Session, key: str):
     except (TypeError, ValueError) as exc:
         # The admin set this in the UI and it is quietly not in force: the app runs on the env
         # default while the settings page goes on showing the value that was saved.
-        log.warning(
-            "a stored setting could not be coerced; the default is used instead",
-            extra=logs.event(
-                "sysconfig.override_uncoercible", key=s.key, reason=type(exc).__name__
-            ),
-        )
+        if (s.key, raw) not in _coerce_warned:
+            _coerce_warned.add((s.key, raw))
+            log.warning(
+                "a stored setting could not be coerced; the default is used instead",
+                extra=logs.event(
+                    "sysconfig.override_uncoercible", key=s.key, reason=type(exc).__name__
+                ),
+            )
         return _default(s)