feat(ws): implement WebSocket cluster mode with Redis Pub/Sub

Introduce a new WebSocket messaging architecture that supports both standalone and cluster modes. This allows for horizontal scaling of WebSocket servers by using Redis Pub/Sub to synchronize messages across multiple instances.

Key changes:
- Added `ws.MessagePublisher` interface to abstract message distribution.
- Implemented `ws.Bus` to handle cluster-mode messaging via Redis.
- Added `ws.OnlineTracker` to manage user online status across the cluster.
- Refactored multiple services (Chat, Group, Push, Call, etc.) to use the new `MessagePublisher` instead of a concrete `ws.Hub`.
- Added WebSocket configuration options (mode, instance ID, channel, TTL, heartbeat) to `config.yaml` and `config.go`.
- Updated dependency injection with Wire to support the new publisher and Redis client.
- Improved logging by replacing standard `log` with `zap` in several service components.

internal/wire/infrastructure.go

@@ -46,8 +46,8 @@ var InfrastructureSet = wire.NewSet(
 	ProvideBuiltinHooks,
 	ProvideModerationHooks,
 
-	// WebSocket Hub
-	ProvideWSHub,
+	// WebSocket MessagePublisher
+	ProvideWSMessagePublisher,
 
 	// 外部服务客户端
 	ProvideOpenAIClient,
@@ -163,9 +163,32 @@ func ProvideModerationHooks(
 	return moderationHooks
 }
 
-// ProvideWSHub 提供 WebSocket Hub
-func ProvideWSHub() *ws.Hub {
-	return ws.NewHub()
+// ProvideWSMessagePublisher 提供 WebSocket 消息发布器
+// standalone 模式返回 *Hub，cluster 模式返回 *Bus（组合 Hub + Redis Pub/Sub）
+func ProvideWSMessagePublisher(cfg *config.Config, redisClient *redis.Client) ws.MessagePublisher {
+	hub := ws.NewHub()
+
+	if cfg.WebSocket.Mode == "cluster" && redisClient != nil {
+		bus := ws.NewBus(hub, redisClient.GetClient(), &ws.WSClusterConfig{
+			InstanceID:        cfg.WebSocket.Cluster.InstanceID,
+			MsgChannel:        cfg.WebSocket.Cluster.MsgChannel,
+			OnlineTTL:         cfg.WebSocket.Cluster.OnlineTTL,
+			HeartbeatInterval: cfg.WebSocket.Cluster.HeartbeatInterval,
+		})
+		if err := bus.Start(); err != nil {
+			zap.L().Error("Failed to start WebSocket Bus, falling back to standalone mode",
+				zap.Error(err),
+			)
+			return hub
+		}
+		zap.L().Info("WebSocket running in cluster mode",
+			zap.String("instance_id", bus.InstanceID()),
+		)
+		return bus
+	}
+
+	zap.L().Info("WebSocket running in standalone mode")
+	return hub
 }
 
 // ProvideOpenAIClient 提供 OpenAI 客户端