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/model/conversation_version_log.go

@@ -0,0 +1,13 @@
+package model
+
+import "time"
+
+// ConversationVersionLog 会话版本日志（用于增量同步）
+type ConversationVersionLog struct {
+	ID             uint      `gorm:"primaryKey;autoIncrement"`
+	UserID         string    `gorm:"not null;size:36;index:idx_vlog_user_version,priority:1"`
+	ConversationID string    `gorm:"not null;size:20;index:idx_vlog_conv"`
+	Version        int64     `gorm:"not null;index:idx_vlog_user_version,priority:2"`
+	ChangeType     string    `gorm:"not null;type:varchar(20)"` // new_msg, read, pin, unpin, mute, unmute, hide, group_update
+	CreatedAt      time.Time `gorm:"autoCreateTime"`
+}