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/sora/adaptor.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"strconv"
 	"strings"
 
 	"github.com/QuantumNous/new-api/common"
@@ -11,6 +12,7 @@ import (
 	"github.com/QuantumNous/new-api/dto"
 	"github.com/QuantumNous/new-api/model"
 	"github.com/QuantumNous/new-api/relay/channel"
+	taskcommon "github.com/QuantumNous/new-api/relay/channel/task/taskcommon"
 	relaycommon "github.com/QuantumNous/new-api/relay/common"
 	"github.com/QuantumNous/new-api/service"
 
@@ -56,6 +58,7 @@ type responseTask struct {
 // ============================
 
 type TaskAdaptor struct {
+	taskcommon.BaseBilling
 	ChannelType int
 	apiKey      string
 	baseURL     string
@@ -68,15 +71,15 @@ func (a *TaskAdaptor) Init(info *relaycommon.RelayInfo) {
 }
 
 func validateRemixRequest(c *gin.Context) *dto.TaskError {
-	var req struct {
-		Prompt string `json:"prompt"`
-	}
+	var req relaycommon.TaskSubmitReq
 	if err := common.UnmarshalBodyReusable(c, &req); err != nil {
 		return service.TaskErrorWrapperLocal(err, "invalid_request", http.StatusBadRequest)
 	}
 	if strings.TrimSpace(req.Prompt) == "" {
 		return service.TaskErrorWrapperLocal(fmt.Errorf("field prompt is required"), "invalid_request", http.StatusBadRequest)
 	}
+	// 存储原始请求到 context，与 ValidateMultipartDirect 路径保持一致
+	c.Set("task_request", req)
 	return nil
 }
 
@@ -87,6 +90,41 @@ func (a *TaskAdaptor) ValidateRequestAndSetAction(c *gin.Context, info *relaycom
 	return relaycommon.ValidateMultipartDirect(c, info)
 }
 
+// EstimateBilling 根据用户请求的 seconds 和 size 计算 OtherRatios。
+func (a *TaskAdaptor) EstimateBilling(c *gin.Context, info *relaycommon.RelayInfo) map[string]float64 {
+	// remix 路径的 OtherRatios 已在 ResolveOriginTask 中设置
+	if info.Action == constant.TaskActionRemix {
+		return nil
+	}
+
+	req, err := relaycommon.GetTaskRequest(c)
+	if err != nil {
+		return nil
+	}
+
+	seconds, _ := strconv.Atoi(req.Seconds)
+	if seconds == 0 {
+		seconds = req.Duration
+	}
+	if seconds <= 0 {
+		seconds = 4
+	}
+
+	size := req.Size
+	if size == "" {
+		size = "720x1280"
+	}
+
+	ratios := map[string]float64{
+		"seconds": float64(seconds),
+		"size":    1,
+	}
+	if size == "1792x1024" || size == "1024x1792" {
+		ratios["size"] = 1.666667
+	}
+	return ratios
+}
+
 func (a *TaskAdaptor) BuildRequestURL(info *relaycommon.RelayInfo) (string, error) {
 	if info.Action == constant.TaskActionRemix {
 		return fmt.Sprintf("%s/v1/videos/%s/remix", a.baseURL, info.OriginTaskID), nil