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

main.go

@@ -19,6 +19,7 @@ import (
 	"github.com/QuantumNous/new-api/middleware"
 	"github.com/QuantumNous/new-api/model"
 	"github.com/QuantumNous/new-api/oauth"
+	"github.com/QuantumNous/new-api/relay"
 	"github.com/QuantumNous/new-api/router"
 	"github.com/QuantumNous/new-api/service"
 	_ "github.com/QuantumNous/new-api/setting/performance_setting"
@@ -111,6 +112,15 @@ func main() {
 	// Subscription quota reset task (daily/weekly/monthly/custom)
 	service.StartSubscriptionQuotaResetTask()
 
+	// Wire task polling adaptor factory (breaks service -> relay import cycle)
+	service.GetTaskAdaptorFunc = func(platform constant.TaskPlatform) service.TaskPollingAdaptor {
+		a := relay.GetTaskAdaptor(platform)
+		if a == nil {
+			return nil
+		}
+		return a
+	}
+
 	if common.IsMasterNode && constant.UpdateTask {
 		gopool.Go(func() {
 			controller.UpdateMidjourneyTaskBulk()