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/pkg/ws/hub.go

@@ -31,11 +31,12 @@ type Event struct {
 
 // Client 表示一个WebSocket客户端连接
 type Client struct {
-	ID         uint64
-	UserID     string
-	Send       chan []byte
-	Quit       chan struct{}
-	PendingAcks map[string]time.Time
+	ID              uint64
+	UserID          string
+	Send            chan []byte
+	Quit            chan struct{}
+	PendingAcks     map[string]time.Time
+	CompressEnabled bool // 客户端是否启用 gzip 压缩
 }
 
 // ErrConnectionLimit 连接数限制错误