feat(chat): implement sequence pre-allocation, versioned sync, and push worker

Introduce several performance and synchronization enhancements:
- Implement `SeqBufferManager` to allow sequence number pre-allocation via Redis Lua scripts, reducing atomic increment overhead.
- Add `PushWorker` to handle asynchronous message pushing using Redis Streams.
- Implement incremental conversation synchronization via `ConversationVersionLog` to allow clients to fetch only recent changes.
- Add support for Gzip compression in WebSocket communications to reduce bandwidth usage.
- Update dependency injection and configuration to support these new components.

internal/handler/message_handler.go

@@ -585,6 +585,37 @@ func (h *MessageHandler) HandleGetSyncData(c *gin.Context) {
 	})
 }
 
+// HandleGetSyncByVersion 增量同步：按版本号获取会话变更
+// GET /api/v1/conversations/sync?version=0&limit=100
+func (h *MessageHandler) HandleGetSyncByVersion(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		response.Unauthorized(c, "")
+		return
+	}
+
+	versionStr := c.DefaultQuery("version", "0")
+	sinceVersion, err := strconv.ParseInt(versionStr, 10, 64)
+	if err != nil || sinceVersion < 0 {
+		response.BadRequest(c, "invalid version parameter")
+		return
+	}
+
+	limitStr := c.DefaultQuery("limit", "100")
+	limit, err := strconv.Atoi(limitStr)
+	if err != nil || limit < 1 {
+		limit = 100
+	}
+
+	result, err := h.chatService.GetSyncByVersion(c.Request.Context(), userID, sinceVersion, limit)
+	if err != nil {
+		response.InternalServerError(c, err.Error())
+		return
+	}
+
+	response.Success(c, result)
+}
+
 // GetConversationUnreadCount 获取单个会话的未读数
 // GET /api/conversations/:id/unread/count
 func (h *MessageHandler) GetConversationUnreadCount(c *gin.Context) {