refactor(task): extract billing and polling logic from controller to service layer

Restructure the task relay system for better separation of concerns:
- Extract task billing into service/task_billing.go with unified settlement flow
- Move task polling loop from controller to service/task_polling.go (supports Suno + video platforms)
- Split RelayTask into fetch/submit paths with dedicated retry logic (taskSubmitWithRetry)
- Add TaskDto, TaskResponse generics, and FetchReq to dto/task.go
- Add taskcommon/helpers.go for shared task adaptor utilities
- Remove controller/task_video.go (logic consolidated into service layer)
- Update all task adaptors (ali, doubao, gemini, hailuo, jimeng, kling, sora, suno, vertex, vidu)
- Simplify frontend task logs to use new TaskDto response format

relay/common/relay_info.go

@@ -118,8 +118,12 @@ type RelayInfo struct {
 	SendResponseCount      int
 	ReceivedResponseCount  int
 	FinalPreConsumedQuota  int // 最终预消耗的配额
+	// ForcePreConsume 为 true 时禁用 BillingSession 的信任额度旁路，
+	// 强制预扣全额。用于异步任务（视频/音乐生成等），因为请求返回后任务仍在运行，
+	// 必须在提交前锁定全额。
+	ForcePreConsume bool
 	// Billing 是计费会话，封装了预扣费/结算/退款的统一生命周期。
-	// 免费模型和按次计费（MJ/Task）时为 nil。
+	// 免费模型时为 nil。
 	Billing BillingSettler
 	// BillingSource indicates whether this request is billed from wallet quota or subscription.
 	// "" or "wallet" => wallet; "subscription" => subscription
@@ -525,8 +529,10 @@ func GenRelayInfo(c *gin.Context, relayFormat types.RelayFormat, request dto.Req
 		return nil, errors.New("request is not a OpenAIResponsesCompactionRequest")
 	case types.RelayFormatTask:
 		info = genBaseRelayInfo(c, nil)
+		info.TaskRelayInfo = &TaskRelayInfo{}
 	case types.RelayFormatMjProxy:
 		info = genBaseRelayInfo(c, nil)
+		info.TaskRelayInfo = &TaskRelayInfo{}
 	default:
 		err = errors.New("invalid relay format")
 	}
@@ -608,6 +614,9 @@ func (info *RelayInfo) HasSendResponse() bool {
 type TaskRelayInfo struct {
 	Action       string
 	OriginTaskID string
+	// PublicTaskID 是提交时预生成的 task_xxxx 格式公开 ID，
+	// 供 DoResponse 在返回给客户端时使用（避免暴露上游真实 ID）。
+	PublicTaskID string
 
 	ConsumeQuota bool
 }
@@ -667,11 +676,11 @@ func (t *TaskSubmitReq) UnmarshalJSON(data []byte) error {
 func (t *TaskSubmitReq) UnmarshalMetadata(v any) error {
 	metadata := t.Metadata
 	if metadata != nil {
-		metadataBytes, err := json.Marshal(metadata)
+		metadataBytes, err := common.Marshal(metadata)
 		if err != nil {
 			return fmt.Errorf("marshal metadata failed: %w", err)
 		}
-		err = json.Unmarshal(metadataBytes, v)
+		err = common.Unmarshal(metadataBytes, v)
 		if err != nil {
 			return fmt.Errorf("unmarshal metadata to target failed: %w", err)
 		}