feat: fix deepseek tool call bug

pkg/providers/openai_compat/provider.go

@@ -285,6 +285,7 @@ func parseResponse(body []byte) (*LLMResponse, error) {
 type openaiMessage struct {
 	Role             string     `json:"role"`
 	Content          string     `json:"content"`
+	ReasoningContent string     `json:"reasoning_content,omitempty"`
 	ToolCalls        []ToolCall `json:"tool_calls,omitempty"`
 	ToolCallID       string     `json:"tool_call_id,omitempty"`
 }
@@ -298,6 +299,7 @@ func stripSystemParts(messages []Message) []openaiMessage {
 		out[i] = openaiMessage{
 			Role:             m.Role,
 			Content:          m.Content,
+			ReasoningContent: m.ReasoningContent,
 			ToolCalls:        m.ToolCalls,
 			ToolCallID:       m.ToolCallID,
 		}