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/main/runtime/mpv-jellyfin-defaults.ts

@@ -1,4 +1,5 @@
 import type { MpvRuntimeClientLike } from '../../core/services/mpv';
+import { getDefaultMpvSocketPath } from '../../shared/mpv-socket-path';
 
 export function createApplyJellyfinMpvDefaultsHandler(deps: {
   sendMpvCommandRuntime: (client: MpvRuntimeClientLike, command: [string, string, string]) => void;
@@ -17,9 +18,6 @@ export function createApplyJellyfinMpvDefaultsHandler(deps: {
 
 export function createGetDefaultSocketPathHandler(deps: { platform: string }) {
   return (): string => {
-    if (deps.platform === 'win32') {
-      return '\\\\.\\pipe\\subminer-socket';
-    }
-    return '/tmp/subminer-socket';
+    return getDefaultMpvSocketPath(deps.platform as NodeJS.Platform);
   };
 }