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.

frontend/src/lib/clipRange.ts

@@ -1,6 +1,7 @@
 // The range an ad-hoc clip is cut from, marked in a player: the rules the clip panel's handles, its
 // In / Out fields and the players' `[` / `]` keys all go by, so every way of marking keeps a range the
-// server takes (backend downloads/clip.py: at least MIN_CLIP_S, at most MAX_CLIP_S — the owner's cap).
+// server takes (backend downloads/clip.py: at least MIN_CLIP_S, at most MAX_CLIP_S — the owner's cap;
+// clipLimits.contract.test.ts holds the two copies equal).
 
 const MIN_CLIP_S = 1;
 export const MAX_CLIP_S = 600;
@@ -53,3 +54,13 @@ export function zoomWindow(r: ClipRange, duration: number): { from: number; to:
   const pad = Math.max(5, (r.end - r.start) * 0.25);
   return { from: Math.max(0, r.start - pad), to: Math.min(duration, r.end + pad) };
 }
+
+/** The `[` key: In at the playhead `t`, opening a range there when none is marked yet. */
+export function markInAt(r: ClipRange | null, t: number, duration: number): ClipRange {
+  return markIn(r ?? openAt(t, duration), t, duration);
+}
+
+/** The `]` key: Out at the playhead `t`; with no range yet, one that ENDS there. */
+export function markOutAt(r: ClipRange | null, t: number, duration: number): ClipRange {
+  return markOut(r ?? openAt(Math.max(0, t - DEFAULT_CLIP_S), duration), t, duration);
+}