merge main (0.78.2) into playback-class before release

# Conflicts:
#	backend/app/plex/stream.py

backend/app/routes/plex/playback.py

@@ -554,14 +554,16 @@ def stream_session(
         raise HTTPException(status_code=404, detail="Media file not found on disk")
     # Report the REAL media start (the keyframe ffmpeg landed on, which hls.js zero-bases to), not the
     # requested offset — the client's absolute clock and the subtitle cue-shift both key off this.
-    # `transcode`/`hw` let the player show an honest cold-start ("Preparing stream…") and surface the
-    # active mode + encoder in the stats overlay; both segment streams are otherwise identical.
+    # `transcode`/`hw`/`tonemap` let the player show an honest cold-start ("Preparing stream…") and
+    # surface the active mode + encoder in the stats overlay (`tonemap` = the HW HDR→SDR path); both
+    # segment streams are otherwise identical.
     return {
         "mode": "hls",
         "start_s": s.media_start_s,
         "url": f"/api/plex/stream/{it.rating_key}/hls/{s.entry}",
         "transcode": s.transcode,
         "hw": s.hw,
+        "tonemap": s.tonemap,
     }