feat(stats): wire stats server, overlay, and CLI into main process

- Stats server auto-start on immersion tracker init
- Stats overlay toggle via keybinding and IPC
- Stats CLI command (subminer stats) with cleanup mode
- mpv plugin menu integration for stats toggle
- CLI args for --stats, --stats-cleanup, --stats-response-path

src/main/runtime/cli-command-context-deps.test.ts

@@ -54,6 +54,9 @@ test('build cli command context deps maps handlers and values', () => {
       mediaTitle: 'Test',
       entryCount: 10,
     }),
+    runStatsCommand: async () => {
+      calls.push('run-stats');
+    },
     runJellyfinCommand: async () => {
       calls.push('run-jellyfin');
     },