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/common/relay_utils.go

@@ -173,16 +173,10 @@ func ValidateMultipartDirect(c *gin.Context, info *RelayInfo) *dto.TaskError {
 		if model == "sora-2-pro" && !lo.Contains([]string{"720x1280", "1280x720", "1792x1024", "1024x1792"}, size) {
 			return createTaskError(fmt.Errorf("sora-2 size is invalid"), "invalid_size", http.StatusBadRequest, true)
 		}
-		info.PriceData.OtherRatios = map[string]float64{
-			"seconds": float64(seconds),
-			"size":    1,
-		}
-		if lo.Contains([]string{"1792x1024", "1024x1792"}, size) {
-			info.PriceData.OtherRatios["size"] = 1.666667
-		}
+		// OtherRatios 已移到 Sora adaptor 的 EstimateBilling 中设置
 	}
 
-	info.Action = action
+	storeTaskRequest(c, info, action, req)
 
 	return nil
 }