Fix MPV menu: resolve Lua syntax error and enhance logging

- Remove extra 'end)' that caused '<eof>' expected syntax error at line 2834
- Add comprehensive logging to M.show_menu() with [MENU] prefix
- Add logging wrappers to keybindings (m and mbtn_right)
- Implement fallback menu opening methods (commandv and command)
- Fix audio-display mpv.conf setting to 'no' (was invalid 'yes')

MPV/portable_config/mpv.conf

@@ -13,7 +13,7 @@ ontop=yes
 autofit=45%
 # Avoid showing embedded cover art for audio-only files if uosc isn't working,
 # but we keep it enabled for now to ensure a window exists.
-audio-display=yes
+audio-display=no
 keepaspect=no
 video-unscaled=no
 cursor-autohide=1000