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/types.ts

@@ -111,6 +111,9 @@ export interface Args {
   jellyfinPlay: boolean;
   jellyfinDiscovery: boolean;
   dictionary: boolean;
+  stats: boolean;
+  statsCleanup?: boolean;
+  statsCleanupVocab?: boolean;
   dictionaryTarget?: string;
   doctor: boolean;
   configPath: boolean;