fix: 修复system_instruction到systemInstruction的转换并修正回调URL变量名

确保在请求体中正确处理system_instruction到systemInstruction的转换，同时修正回调URL变量名从localUrl到url以匹配实际使用场景

src/gemini/antigravity-core.js

@@ -625,6 +625,12 @@ function toGeminiApiResponse(antigravityResponse) {
  */
 function ensureRolesInContents(requestBody, modelName) {
     delete requestBody.model;
+    // delete requestBody.system_instruction;
+    // delete requestBody.systemInstruction;
+    if (requestBody.system_instruction) {
+        requestBody.systemInstruction = requestBody.system_instruction;
+        delete requestBody.system_instruction;
+    }
 
     // 提取现有的系统提示词
     let originalSystemPrompt = requestBody.systemInstruction;

static/app/provider-manager.js

@@ -829,7 +829,7 @@ function showAuthModal(authUrl, authInfo) {
                             // 通过服务端API处理手动输入的回调URL
                             window.apiClient.post('/oauth/manual-callback', {
                                 provider: authInfo.provider,
-                                callbackUrl: localUrl.href,
+                                callbackUrl: url.href, //使用localhost访问
                                 authMethod: authInfo.authMethod
                             })
                                 .then(response => {