refactor: 重构消息类型的初始化逻辑，新增各消息类型的构造函数以提高代码可读性和可维护性

message/share.go

@@ -21,10 +21,14 @@ type ShareMessageData struct {
 
 func init() {
 	RegisterMessageType(TypeShare, func() CQMessage {
-		return &ShareMessage{Type: TypeShare}
+		return NewShareMessage()
 	})
 }
 
+func NewShareMessage() *ShareMessage {
+	return &ShareMessage{Type: TypeShare}
+}
+
 func (msg *ShareMessage) SetData(data json.RawMessage) error {
 	return json.Unmarshal(data, &msg.Data)
 }