Gapless playback still gapped between tracks on network streams: mpv
only opened the armed next track's stream at the moment the current one
ended, so any server whose connect+probe outlasts the audio output's
buffered tail (~0.5s) - remote Plex over TLS, a transcode session
starting up - produced an audible dropout at every transition.
Enable mpv's prefetch-playlist when arming a network track so the open
happens while the current track still plays. Measured on a Pixel 7 the
boundary goes from 60-233ms of inline network work to 9-16ms with no
network activity at all; a failed or superseded prefetch falls back to
the old boundary open. Local fdclose:// arms keep prefetch off: an
early open would consume the fd while playlist-pos still reads 0,
breaking _clearArmedNext's "provably never opened" close proof.
close#1869
setNext() appended raw content:// URIs that mpv cannot open, stalling
playback at the SD-card-download track boundary. Convert to fdclose://
like open(), track the armed fd, and reclaim it via a new closeContentFd
method when the entry is dropped unplayed (close only when provably
unconsumed — playlist-pos 0 before and after the remove; leak on doubt).
The playlist-pos pre-check also keeps the clear path from removing the
playing entry when mpv rolls into the armed track mid-clear.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>