feat(config): unify mpv plugin options under main config and add CSS/Ani

- Replace subminer.conf plugin config with mpv.* fields in config.jsonc
- Add socketPath, backend, autoStartSubMiner, pauseUntilOverlayReady, aniskipEnabled/buttonKey, subminerBinaryPath to mpv config
- Add subtitleSidebar.css field; migrate legacy sidebar appearance fields
- Add paintOrder and WebkitTextStroke to subtitle style options
- Update default subtitle/sidebar fontFamily to CJK-first stack
- Fix overlay visible state surviving mpv y-r restart
- Fix live config saves applying subtitle CSS immediately to open overlays
- Migrate legacy primary/secondary subtitle appearance into subtitleStyle.css on load
- Switch AniSkip button key setting to click-to-learn key capture

src/settings/key-input.test.ts

@@ -58,6 +58,23 @@ test('keyboardEventToConfigKey formats bare key-code fields without modifiers',
   );
 });
 
+test('keyboardEventToConfigKey formats mpv key bindings from learned input', () => {
+  assert.equal(
+    keyboardEventToConfigKey(
+      { code: 'Tab', key: 'Tab', ctrlKey: false, altKey: false, shiftKey: false, metaKey: false },
+      'mpv-key',
+    ),
+    'TAB',
+  );
+  assert.equal(
+    keyboardEventToConfigKey(
+      { code: 'KeyK', key: 'K', ctrlKey: true, altKey: false, shiftKey: true, metaKey: false },
+      'mpv-key',
+    ),
+    'Ctrl+Shift+K',
+  );
+});
+
 test('MPV keybinding rows save default key moves as a disable plus replacement', () => {
   const defaults: Keybinding[] = [{ key: 'Space', command: ['cycle', 'pause'] }];
   const rows = createMpvKeybindingRows(defaults, []);