Revert "feat: gemini-2.5-flash-image-preview 文本和图片输出计费"

This reverts commit a45513a7a6.

setting/operation_setting/tools.go

@@ -24,10 +24,6 @@ const (
 	ClaudeWebSearchPrice = 10.00
 )
 
-const (
-	Gemini25FlashImagePreviewImageOutputPrice = 30.00
-)
-
 func GetClaudeWebSearchPricePerThousand() float64 {
 	return ClaudeWebSearchPrice
 }
@@ -69,10 +65,3 @@ func GetGeminiInputAudioPricePerMillionTokens(modelName string) float64 {
 	}
 	return 0
 }
-
-func GetGeminiImageOutputPricePerMillionTokens(modelName string) float64 {
-	if strings.HasPrefix(modelName, "gemini-2.5-flash-image-preview") {
-		return Gemini25FlashImagePreviewImageOutputPrice
-	}
-	return 0
-}