Add Bilibili video analysis plugin

Introduced a new 'bilibli' plugin for Bilibili video parsing and AI-based content analysis. Added plugin manifest, base module for video info retrieval and analysis, and plugin integration with tool registration. Updated .gitignore to include the new plugin directory.

plugins/bilibli/__init__.py

@@ -0,0 +1,8 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Bilibili 插件包
+提供B站视频观看体验功能，像真实用户一样浏览和评价视频
+"""
+
+# 插件会通过 @register_plugin 装饰器自动注册，这里不需要额外的导入