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/plex/sync.py

@@ -64,9 +64,11 @@ def classify_playable(vcodec: str | None, acodec: str | None, container: str | N
 # outside it (AV1, MPEG-4 ASP/XviD…) is software-only even on the iGPU (it can't decode it to feed its
 # own encoder).
 HW_DECODABLE_CODECS = frozenset({"h264", "hevc", "h265", "vp9", "vc1", "mpeg2video"})
-# Color-transfer values marking an HDR source (PQ / HLG). A 10-bit/HDR source breaks the VAAPI
-# scale=nv12 path on Gen 9.5 (see plex.stream) → software transcode, so it counts as NOT HW-capable.
-_HDR_TRANSFERS = frozenset({"smpte2084", "arib-std-b67"})
+# Color-transfer values marking an HDR source (PQ / HLG). THE single source of this set: plex.stream
+# (the tonemap choice) and downloads.clip (a clip's tonemap) import it here, so a transfer added for
+# one is tonemapped by all. A 10-bit/HDR source breaks the VAAPI scale=nv12 path on Gen 9.5 (see
+# plex.stream) → software transcode, so it counts as NOT HW-capable.
+HDR_TRANSFERS = frozenset({"smpte2084", "arib-std-b67"})
 
 
 def transcode_hw_capable(
@@ -107,7 +109,7 @@ def _video_stream_props(meta: dict) -> tuple[int | None, bool]:
                 # whole library would drown the sync's own lines.
                 except (TypeError, ValueError):
                     depth = None
-                hdr = str(s.get("colorTrc") or "").lower() in _HDR_TRANSFERS
+                hdr = str(s.get("colorTrc") or "").lower() in HDR_TRANSFERS
                 return depth, hdr
     return None, False