feat: add Thought field to GeminiPart and update response handling in streamResponseGeminiChat2OpenAI

relay/channel/gemini/dto.go

@@ -54,6 +54,7 @@ type GeminiFileData struct {
 
 type GeminiPart struct {
 	Text                string                         `json:"text,omitempty"`
+	Thought             bool                           `json:"thought,omitempty"`
 	InlineData          *GeminiInlineData              `json:"inlineData,omitempty"`
 	FunctionCall        *FunctionCall                  `json:"functionCall,omitempty"`
 	FunctionResponse    *FunctionResponse              `json:"functionResponse,omitempty"`

relay/channel/gemini/relay-gemini.go

@@ -596,6 +596,7 @@ func streamResponseGeminiChat2OpenAI(geminiResponse *GeminiChatResponse) (*dto.C
 		}
 		var texts []string
 		isTools := false
+		isThought := false
 		if candidate.FinishReason != nil {
 			// p := GeminiConvertFinishReason(*candidate.FinishReason)
 			switch *candidate.FinishReason {
@@ -620,6 +621,9 @@ func streamResponseGeminiChat2OpenAI(geminiResponse *GeminiChatResponse) (*dto.C
 					call.SetIndex(len(choice.Delta.ToolCalls))
 					choice.Delta.ToolCalls = append(choice.Delta.ToolCalls, *call)
 				}
+			} else if part.Thought {
+				isThought = true
+				texts = append(texts, part.Text)
 			} else {
 				if part.ExecutableCode != nil {
 					texts = append(texts, "```"+part.ExecutableCode.Language+"\n"+part.ExecutableCode.Code+"\n```\n")
@@ -632,7 +636,11 @@ func streamResponseGeminiChat2OpenAI(geminiResponse *GeminiChatResponse) (*dto.C
 				}
 			}
 		}
-		choice.Delta.SetContentString(strings.Join(texts, "\n"))
+		if isThought {
+			choice.Delta.SetReasoningContent(strings.Join(texts, "\n"))
+		} else {
+			choice.Delta.SetContentString(strings.Join(texts, "\n"))
+		}
 		if isTools {
 			choice.FinishReason = &constant.FinishReasonToolCalls
 		}