add app control server for launcher-to-app attachment

- Launcher detects a running app via control socket and attaches without spawning a new process
- Own-lifecycle app launches now pass --background --managed-playback; borrowed apps skip --background
- Separate plain subtitle websocket (tokens: []) from annotation websocket
- Default pauseVideoOnHover to true; update docs and config.example.jsonc
- Setup: remove plugin readiness card, add Open SubMiner Settings button

changes/plain-websocket-annotations.md

@@ -0,0 +1,4 @@
+type: fixed
+area: websocket
+
+- WebSocket: Kept the regular subtitle websocket plain-text only; annotation spans and token metadata now stay on the annotation websocket.