feat: add rate limiting and improve event handling

- Introduced rate limiting configuration in config.toml with options for enabling, requests per second (RPS), and burst capacity.
- Enhanced event handling in the OneBot11 adapter to ignore messages sent by the bot itself.
- Updated the dispatcher to register rate limit middleware based on configuration settings.
- Refactored WebSocket message handling to support flexible JSON parsing and improved event type detection.
- Removed deprecated echo plugin and associated tests to streamline the codebase.

internal/protocol/interface.go

@@ -68,6 +68,10 @@ type EventHandler interface {
 	Priority() int
 	// Match 判断是否匹配事件
 	Match(event Event) bool
+	// Name 获取处理器名称
+	Name() string
+	// Description 获取处理器描述
+	Description() string
 }
 
 // Middleware 中间件接口