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/background-launcher-reuse.md

@@ -1,4 +1,4 @@
 type: fixed
 area: launcher
 
-- Reused an already-running background SubMiner app for launcher-opened videos, preserving warmups and keeping the tray app alive after playback closes.
+- Reused an already-running background SubMiner app for launcher-opened videos, closed launcher-owned tray apps after playback ends, and reapplied preferred subtitles for warm launches.

changes/hide-setup-runtime-plugin.md

@@ -0,0 +1,4 @@
+type: changed
+area: setup
+
+- Setup: Removed the bundled mpv runtime plugin readiness card; legacy mpv plugin removal still appears when needed.

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.

changes/setup-subminer-settings-button.md

@@ -0,0 +1,4 @@
+type: added
+area: setup
+
+- Setup: Added an Open SubMiner Settings button to first-run setup and moved Finish setup to the right-side action slot.