fix: Antigravity project_id 获取优化

- API URL 改为只使用 prod 端点
- 刷新 token 时每次调用 LoadCodeAssist 更新 project_id
- 移除随机生成 project_id 的兜底逻辑

backend/internal/service/antigravity_oauth_service.go

@@ -149,12 +149,6 @@ func (s *AntigravityOAuthService) ExchangeCode(ctx context.Context, input *Antig
 		result.ProjectID = loadResp.CloudAICompanionProject
 	}
 
-	// 兜底：随机生成 project_id
-	if result.ProjectID == "" {
-		result.ProjectID = antigravity.GenerateMockProjectID()
-		fmt.Printf("[AntigravityOAuth] 使用随机生成的 project_id: %s\n", result.ProjectID)
-	}
-
 	return result, nil
 }
 
@@ -236,16 +230,25 @@ func (s *AntigravityOAuthService) RefreshAccountToken(ctx context.Context, accou
 		return nil, err
 	}
 
-	// 保留原有的 project_id 和 email
-	existingProjectID := strings.TrimSpace(account.GetCredential("project_id"))
-	if existingProjectID != "" {
-		tokenInfo.ProjectID = existingProjectID
-	}
+	// 保留原有的 email
 	existingEmail := strings.TrimSpace(account.GetCredential("email"))
 	if existingEmail != "" {
 		tokenInfo.Email = existingEmail
 	}
 
+	// 每次刷新都调用 LoadCodeAssist 更新 project_id
+	client := antigravity.NewClient(proxyURL)
+	loadResp, _, err := client.LoadCodeAssist(ctx, tokenInfo.AccessToken)
+	if err != nil {
+		// 失败时保留原有的 project_id
+		existingProjectID := strings.TrimSpace(account.GetCredential("project_id"))
+		if existingProjectID != "" {
+			tokenInfo.ProjectID = existingProjectID
+		}
+	} else if loadResp != nil && loadResp.CloudAICompanionProject != "" {
+		tokenInfo.ProjectID = loadResp.CloudAICompanionProject
+	}
+
 	return tokenInfo, nil
 }
 

backend/internal/service/antigravity_quota_fetcher.go

@@ -31,11 +31,6 @@ func (f *AntigravityQuotaFetcher) FetchQuota(ctx context.Context, account *Accou
 	accessToken := account.GetCredential("access_token")
 	projectID := account.GetCredential("project_id")
 
-	// 如果没有 project_id，生成一个随机的
-	if projectID == "" {
-		projectID = antigravity.GenerateMockProjectID()
-	}
-
 	client := antigravity.NewClient(proxyURL)
 
 	// 调用 API 获取配额