fix autoplay gate to hold pause until subtitle prime and tokenization re

- use pluginRuntimeConfig.autoStart (not effectivePluginRuntimeConfig) so pause-until-ready is preserved when attaching to a background app
- await subtitle priming before signaling autoplay readiness
- move sub-auto/sid defaults to start-file so they are not overwritten after track load

launcher/commands/playback-command.test.ts

@@ -261,7 +261,7 @@ test('plugin auto-start playback attaches a warm background app through the laun
   });
 
   assert.deepEqual(calls, ['startMpv', 'startOverlay:--show-visible-overlay --texthooker']);
-  assert.equal(receivedStartMpvOptions[0]?.startPaused, false);
+  assert.equal(receivedStartMpvOptions[0]?.startPaused, true);
   assert.equal(
     (receivedStartMpvOptions[0]?.runtimePluginConfig as { autoStart?: boolean } | undefined)
       ?.autoStart,