feat(stats): add launcher stats command and build integration

- Launcher stats subcommand with cleanup mode
- Stats frontend build integrated into Makefile
- CI workflow updated for stats package
- Config example updated with stats section
- mpv plugin menu entry for stats toggle

launcher/mpv.test.ts

@@ -133,6 +133,7 @@ function makeArgs(overrides: Partial<Args> = {}): Args {
     jellyfinPlay: false,
     jellyfinDiscovery: false,
     dictionary: false,
+    stats: false,
     doctor: false,
     configPath: false,
     configShow: false,