fix(clip): a clip is held to its owner's storage cap, and its limits and failures say the server's truth

- The cut file is measured against what its owner has left, for a YouTube range (whose fetch never
  reads yt-dlp's size ceiling) and for a Plex clip (which fetches nothing), before the fetch and
  again before it is placed; a refusal leaves the asset pending for a Retry.
- A silent Plex file is cut silent; a file the probe cannot read says so.
- A second job on a failed or renamed clip gets the same YouTube diagnosis and the fetched title.
- The "too long" refusal names the server's cap; a contract test holds the client's copies of the
  clip limits to clip.py; the shipped player clients are pinned against the installed yt-dlp.
- One HDR transfer set and one rating_key lookup; job status words from JobStatus; the display-name
  guard sees subscript writes and the clip route; stale comments and types follow the clip job.

backend/app/routes/downloads.py

@@ -610,10 +610,12 @@ def enqueue_clip(
         spec = clipmod.normalize(
             body.source, body.ref, body.start_s, body.end_s, body.audio_track, crop
         )
-        job = service.enqueue_clip(db, user.id, spec, display_text(body.display_name))
+        display_name = display_text(body.display_name)
+        job = service.enqueue_clip(db, user.id, spec, display_name=display_name)
     except clipmod.ClipError as e:
         status = 404 if e.reason == "not_found" else 422
-        raise HTTPException(status_code=status, detail={"code": "clip", "reason": e.reason}) from e
+        detail = {"code": "clip", "reason": e.reason, **e.params}
+        raise HTTPException(status_code=status, detail=detail) from e
     except quota.QuotaExceeded as e:
         raise HTTPException(status_code=422, detail=_quota_detail(e)) from e
     return _serialize_job(db, job)