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/config/definitions/domain-registry.test.ts

@@ -65,6 +65,7 @@ const UNDOCUMENTED_LEAVES: ReadonlySet<string> = new Set([
   'subtitleStyle.jlptColors.N5',
   'subtitleStyle.letterSpacing',
   'subtitleStyle.lineHeight',
+  'subtitleStyle.paintOrder',
   'subtitleStyle.secondary.backdropFilter',
   'subtitleStyle.secondary.backgroundColor',
   'subtitleStyle.secondary.fontColor',
@@ -75,11 +76,14 @@ const UNDOCUMENTED_LEAVES: ReadonlySet<string> = new Set([
   'subtitleStyle.secondary.fontWeight',
   'subtitleStyle.secondary.letterSpacing',
   'subtitleStyle.secondary.lineHeight',
+  'subtitleStyle.secondary.paintOrder',
   'subtitleStyle.secondary.textRendering',
   'subtitleStyle.secondary.textShadow',
+  'subtitleStyle.secondary.WebkitTextStroke',
   'subtitleStyle.secondary.wordSpacing',
   'subtitleStyle.textRendering',
   'subtitleStyle.textShadow',
+  'subtitleStyle.WebkitTextStroke',
   'subtitleStyle.wordSpacing',
 ]);
 
@@ -101,6 +105,13 @@ test('config option registry includes critical paths and has unique entries', ()
     'anilist.characterDictionary.collapsibleSections.description',
     'mpv.executablePath',
     'mpv.launchMode',
+    'mpv.socketPath',
+    'mpv.backend',
+    'mpv.autoStartSubMiner',
+    'mpv.pauseUntilOverlayReady',
+    'mpv.subminerBinaryPath',
+    'mpv.aniskipEnabled',
+    'mpv.aniskipButtonKey',
     'yomitan.externalProfilePath',
     'immersionTracking.enabled',
   ]) {