Live HDR session on a panel parked in HDR (Match Content off) is labelled SDR for its whole length #887

Reported by an integrator on 7.42.0 (Discord).

Setup: Apple TV output fixed to HDR (e.g. 4K HDR 60), Match Content (Dynamic Range + Frame Rate) off, live MPEG-TS HDR10 channel. The picture is HDR, KSPlayer reports HDR10 on the same channel, videoFormat stays .sdr for the whole session.

Chain:

1. Match Content off: no criteria write ([DisplayCriteria] skipped: Match Content disabled), currentEDRHeadroom stays 1.00 on a panel parked in HDR, so sessionPanelPresentsHDR reads false and presentedVideoFormat(.hdr10, panelPresentsHDR: false) publishes .sdr.
2. The AE#459 correction cannot rescue live: attemptsHDRMasterOnUnprovenPanel && !options.isLive keeps live off the unproven master, so armPlaybackPanelProbe has no master acceptance to read, and the headroom probe samples the same 1.00. republishPanelPresentsHDR never runs.
3. Separately: a proof latched earlier in the process (a VOD title whose master was accepted) is ignored here too. panelPresentsHDR only honours it for attribution == .engineHDR, and a skipped write leaves .hostDriven.

Not a fix: falling back to sourceVideoFormat while hdrEligible is true. eligibleForHDRPlayback / availableHDRModes answer what the panel CAN present, so a box parked in 4K SDR reads eligible as well and would be labelled HDR10 (AE#459/#535). The served track's transfer function describes the source, not the output.

Fix:

• Live attempts the unproven master like VOD. A refusal lands before the first frame (54 to 61 ms measured on VOD), and the live fallback is the existing Live HDR10 master playlist rejected by AVPlayer (-1002), never falls back to media.m3u8 #130 rejoin at the edge, i.e. where the session was joining anyway. The refusal latch still applies.
• With Match Content off, a proof from this foreground stretch counts without an HDR write: nobody can switch the panel, and changing the parked mode means leaving the app, which clears the proof.

Still to confirm on device (no HDR live channel here): parked 4K HDR shows republishing videoFormat sdr -> hdr10; parked 4K SDR shows one -11868/-11848, the media fallback at the live edge and the latch, with no visible stall.