5.14.0

Added

• Subtitles render inside sample-buffer PiP windows: the software path composites active cues into decoded frames while pictureInPictureActive. The system PiP window renders only the display layer, so host-drawn overlays never reach it; a new SubtitleFrameCompositor caches one overlay per cue-set change (text cues in a readable default look via CoreText, bitmap cues width-aligned center-anchored per their PGS/DVB canvas) and GPU-composites it into a pooled buffer of the source pixel format inside the renderer's flush path. Outside PiP nothing changes (fullscreen subtitle drawing stays with the host); any compositing failure passes the original frame through. Covered by SubtitleFrameCompositorTests including a synthetic-buffer integration test.