Refactor code structure for improved readability and maintainability

feat: add JASSUB type definitions and update common.js references

feat: add JASSUB plugin for advanced subtitle rendering in HTML5 video

- Implemented a new JASSUB class for handling subtitle rendering with options for video and canvas targets.
- Added support for both synchronous and asynchronous rendering modes.
- Integrated Web Worker for offloading rendering tasks, improving performance.
- Included methods for managing subtitle tracks, styles, and events.
- Added color space verification and handling to ensure accurate subtitle display.
- Implemented local font access for enhanced typography options in subtitles.
- Introduced a benchmarking feature to assess rendering performance.

refactor: update README and type definitions for artplayer-plugin-jassub

- Removed installation and usage instructions from README.md for clarity.
- Updated index.js to remove direct assignment of jassub instance to art.
- Enhanced type definitions in artplayer-plugin-jassub.d.ts to include detailed JassubOption and JassubInstance interfaces.

docs/assets/js/common.js

@@ -64,6 +64,7 @@
       './assets/ts/artplayer-plugin-vtt-thumbnail.d.ts',
       './assets/ts/artplayer-plugin-document-pip.d.ts',
       './assets/ts/artplayer-plugin-liquid-glass.d.ts',
+      './assets/ts/artplayer-plugin-jassub.d.ts',
       './assets/ts/artplayer-proxy-canvas.d.ts',
       './assets/ts/artplayer-proxy-mediabunny.d.ts',
       './assets/ts/artplayer.d.ts',