Fit any-aspect camera into its tile without cropping

Add --keepaspect-window=no so mpv stops reshaping its window to the
video aspect (which pushed a 4:3 camera below its tile and hid the
bottom behind the neighbour). Combined with keepaspect=yes the video
is letterboxed to fit the tile for any camera type.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/player/player.go

@@ -67,11 +67,17 @@ func (p *Player) args() []string {
 		"--cursor-autohide=always",
 		"--no-border",
 		"--fullscreen=no", // we tile via the compositor, not fullscreen
-		// Keep aspect (letterbox) inside the tile; the compositor owns the
+		// Fit any camera into its tile regardless of the camera's aspect:
-		// window size, not the video. mpv still resizes its window to the
+		//  * keepaspect=yes         → letterbox the video, never crop/stretch
-		// video resolution on load (and mpv 0.35 lacks the flag to disable
+		//  * keepaspect-window=no   → do NOT reshape the window to the video's
-		// that), so the daemon re-asserts each tile's geometry on a timer.
+		//    aspect; accept the tile size the compositor assigns. Without this
+		//    mpv grows the window to e.g. 4:3 and the overflow is hidden under
+		//    the neighbouring tile ("bottom cut off").
+		// mpv still resizes the window to the video's pixel size on load (mpv
+		// 0.35 lacks --auto-window-resize), so the daemon re-asserts each
+		// tile's geometry on a timer.
 		"--keepaspect=yes",
+		"--keepaspect-window=no",
 		"--title=" + p.Title(),
 		"--input-ipc-server=" + p.ipcPath,
 		"--hwdec=" + p.cfg.HWDec,