feat(task): add adaptor billing interface and async settlement framework

Add three billing lifecycle methods to the TaskAdaptor interface:
- EstimateBilling: compute OtherRatios from user request before pricing
- AdjustBillingOnSubmit: adjust ratios from upstream submit response
- AdjustBillingOnComplete: determine final quota at task terminal state

Introduce BaseBilling as embeddable no-op default for adaptors without
custom billing. Move Sora/Ali OtherRatios logic from shared validation
into per-adaptor EstimateBilling implementations.

Add TaskBillingContext to persist pricing params (model_price, group_ratio,
other_ratios) in task private data for async polling settlement.

Extract RecalculateTaskQuota as a general-purpose delta settlement
function and unify polling billing via settleTaskBillingOnComplete
(adaptor-first, then token-based fallback).

relay/channel/task/ali/adaptor.go

@@ -13,6 +13,7 @@ import (
 	"github.com/QuantumNous/new-api/logger"
 	"github.com/QuantumNous/new-api/model"
 	"github.com/QuantumNous/new-api/relay/channel"
+	"github.com/QuantumNous/new-api/relay/channel/task/taskcommon"
 	relaycommon "github.com/QuantumNous/new-api/relay/common"
 	"github.com/QuantumNous/new-api/service"
 	"github.com/samber/lo"
@@ -108,10 +109,10 @@ type AliMetadata struct {
 // ============================
 
 type TaskAdaptor struct {
+	taskcommon.BaseBilling
 	ChannelType int
 	apiKey      string
 	baseURL     string
-	aliReq      *AliVideoRequest
 }
 
 func (a *TaskAdaptor) Init(info *relaycommon.RelayInfo) {
@@ -121,17 +122,7 @@ func (a *TaskAdaptor) Init(info *relaycommon.RelayInfo) {
 }
 
 func (a *TaskAdaptor) ValidateRequestAndSetAction(c *gin.Context, info *relaycommon.RelayInfo) (taskErr *dto.TaskError) {
-	// 阿里通义万相支持 JSON 格式，不使用 multipart
-	var taskReq relaycommon.TaskSubmitReq
-	if err := common.UnmarshalBodyReusable(c, &taskReq); err != nil {
-		return service.TaskErrorWrapper(err, "unmarshal_task_request_failed", http.StatusBadRequest)
-	}
-	aliReq, err := a.convertToAliRequest(info, taskReq)
-	if err != nil {
-		return service.TaskErrorWrapper(err, "convert_to_ali_request_failed", http.StatusInternalServerError)
-	}
-	a.aliReq = aliReq
-	logger.LogJson(c, "ali video request body", aliReq)
+	// ValidateMultipartDirect 负责解析并将原始 TaskSubmitReq 存入 context
 	return relaycommon.ValidateMultipartDirect(c, info)
 }
 
@@ -148,11 +139,21 @@ func (a *TaskAdaptor) BuildRequestHeader(c *gin.Context, req *http.Request, info
 }
 
 func (a *TaskAdaptor) BuildRequestBody(c *gin.Context, info *relaycommon.RelayInfo) (io.Reader, error) {
-	bodyBytes, err := common.Marshal(a.aliReq)
+	taskReq, err := relaycommon.GetTaskRequest(c)
+	if err != nil {
+		return nil, errors.Wrap(err, "get_task_request_failed")
+	}
+
+	aliReq, err := a.convertToAliRequest(info, taskReq)
+	if err != nil {
+		return nil, errors.Wrap(err, "convert_to_ali_request_failed")
+	}
+	logger.LogJson(c, "ali video request body", aliReq)
+
+	bodyBytes, err := common.Marshal(aliReq)
 	if err != nil {
 		return nil, errors.Wrap(err, "marshal_ali_request_failed")
 	}
-
 	return bytes.NewReader(bodyBytes), nil
 }
 
@@ -335,19 +336,33 @@ func (a *TaskAdaptor) convertToAliRequest(info *relaycommon.RelayInfo, req relay
 		return nil, errors.New("can't change model with metadata")
 	}
 
-	info.PriceData.OtherRatios = map[string]float64{
+	return aliReq, nil
+}
+
+// EstimateBilling 根据用户请求参数计算 OtherRatios（时长、分辨率等）。
+// 在 ValidateRequestAndSetAction 之后、价格计算之前调用。
+func (a *TaskAdaptor) EstimateBilling(c *gin.Context, info *relaycommon.RelayInfo) map[string]float64 {
+	taskReq, err := relaycommon.GetTaskRequest(c)
+	if err != nil {
+		return nil
+	}
+
+	aliReq, err := a.convertToAliRequest(info, taskReq)
+	if err != nil {
+		return nil
+	}
+
+	otherRatios := map[string]float64{
 		"seconds": float64(aliReq.Parameters.Duration),
 	}
-
 	ratios, err := ProcessAliOtherRatios(aliReq)
 	if err != nil {
-		return nil, err
+		return otherRatios
 	}
-	for s, f := range ratios {
-		info.PriceData.OtherRatios[s] = f
+	for k, v := range ratios {
+		otherRatios[k] = v
 	}
-
-	return aliReq, nil
+	return otherRatios
 }
 
 // DoRequest delegates to common helper