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/config/config.go

@@ -15,6 +15,7 @@ type Config struct {
 	Log      LogConfig      `toml:"log"`
 	Protocol ProtocolConfig `toml:"protocol"`
 	Bots     []BotConfig    `toml:"bots"`
+	Engine   EngineConfig   `toml:"engine"`
 }
 
 // ServerConfig 服务器配置
@@ -39,6 +40,18 @@ type ProtocolConfig struct {
 	Options map[string]string `toml:"options"`
 }
 
+// EngineConfig 引擎配置
+type EngineConfig struct {
+	RateLimit RateLimitConfig `toml:"rate_limit"`
+}
+
+// RateLimitConfig 限流配置
+type RateLimitConfig struct {
+	Enabled bool `toml:"enabled"` // 是否启用限流
+	RPS     int  `toml:"rps"`     // 每秒请求数
+	Burst   int  `toml:"burst"`   // 突发容量
+}
+
 // BotConfig Bot 配置
 type BotConfig struct {
 	ID       string         `toml:"id"`