feat(billing): enhance task billing process with video input detection and updated pricing logic

- Added `EstimateBilling` function to check for video input in request metadata and return corresponding discount ratios.
- Updated `ModelPriceHelperPerCall` to incorporate new pricing logic based on model ratios and video input.
- Enhanced task billing logs to include model ratio information and adjusted calculations for actual quota based on additional multipliers.
- Introduced `renderTaskBillingProcess` to improve rendering of task billing information in the UI.

relay/channel/task/doubao/constants.go

@@ -10,3 +10,16 @@ var ModelList = []string{
 }
 
 var ChannelName = "doubao-video"
+
+// videoInputRatioMap 视频输入折扣比率（含视频单价 / 不含视频单价）。
+// 管理员应将 ModelRatio 设置为"不含视频"的较高费率，
+// 系统在检测到视频输入时自动乘以此折扣。
+var videoInputRatioMap = map[string]float64{
+	"doubao-seedance-2-0-260128":      28.0 / 46.0, // ~0.6087
+	"doubao-seedance-2-0-fast-260128": 22.0 / 37.0, // ~0.5946
+}
+
+func GetVideoInputRatio(modelName string) (float64, bool) {
+	r, ok := videoInputRatioMap[modelName]
+	return r, ok
+}