Introduces a plugin router registry for registering plugin-specific API routes, static resources, and extension pages. Updates the plugin manager and context to expose the router, and implements backend and frontend support for serving and displaying plugin extension pages in the WebUI. Also adds a demo extension page and static resource to the builtin plugin.
Simplified PluginStoreItem types by removing unused fields and standardizing the minimum version property. Updated frontend plugin store page to use new categories ('官方', '工具', '娱乐', '其它') instead of download-based sorting, aligning with the revised type definitions.
Changed napcat-plugin-builtin to use workspace reference for napcat-types instead of a fixed version. Updated tsconfig to use bundler module resolution and improved Vite config plugin resolution. Enhanced napcat-types package.json exports for better type support.
Introduces the napcat-plugin-builtin package with initialization, message handling, and build configuration. Also adds a type-safe 'call' helper to the action map in napcat-onebot for improved action invocation.
