feat: 支持后台设置是否启用整流开关

backend/internal/service/antigravity_gateway_service.go

@@ -1384,7 +1384,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 		// 优先检测 thinking block 的 signature 相关错误（400）并重试一次：
 		// Antigravity /v1internal 链路在部分场景会对 thought/thinking signature 做严格校验，
 		// 当历史消息携带的 signature 不合法时会直接 400；去除 thinking 后可继续完成请求。
-		if resp.StatusCode == http.StatusBadRequest && isSignatureRelatedError(respBody) {
+		if resp.StatusCode == http.StatusBadRequest && isSignatureRelatedError(respBody) && s.settingService.IsSignatureRectifierEnabled(ctx) {
 			upstreamMsg := strings.TrimSpace(extractAntigravityErrorMessage(respBody))
 			upstreamMsg = sanitizeUpstreamErrorMessage(upstreamMsg)
 			logBody, maxBytes := s.getLogConfig()
@@ -1517,6 +1517,80 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 			}
 		}
 
+		// Budget 整流：检测 budget_tokens 约束错误并自动修正重试
+		if resp.StatusCode == http.StatusBadRequest && respBody != nil && !isSignatureRelatedError(respBody) {
+			errMsg := strings.TrimSpace(extractAntigravityErrorMessage(respBody))
+			if isThinkingBudgetConstraintError(errMsg) && s.settingService.IsBudgetRectifierEnabled(ctx) {
+				appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+					Platform:           account.Platform,
+					AccountID:          account.ID,
+					AccountName:        account.Name,
+					UpstreamStatusCode: resp.StatusCode,
+					UpstreamRequestID:  resp.Header.Get("x-request-id"),
+					Kind:               "budget_constraint_error",
+					Message:            errMsg,
+					Detail:             s.getUpstreamErrorDetail(respBody),
+				})
+
+				// 修正 claudeReq 的 thinking 参数（adaptive 模式不修正）
+				if claudeReq.Thinking == nil || claudeReq.Thinking.Type != "adaptive" {
+					retryClaudeReq := claudeReq
+					retryClaudeReq.Messages = append([]antigravity.ClaudeMessage(nil), claudeReq.Messages...)
+					// 创建新的 ThinkingConfig 避免修改原始 claudeReq.Thinking 指针
+					retryClaudeReq.Thinking = &antigravity.ThinkingConfig{
+						Type:         "enabled",
+						BudgetTokens: BudgetRectifyBudgetTokens,
+					}
+					if retryClaudeReq.MaxTokens < BudgetRectifyMinMaxTokens {
+						retryClaudeReq.MaxTokens = BudgetRectifyMaxTokens
+					}
+
+					logger.LegacyPrintf("service.antigravity_gateway", "Antigravity account %d: detected budget_tokens constraint error, retrying with rectified budget (budget_tokens=%d, max_tokens=%d)", account.ID, BudgetRectifyBudgetTokens, BudgetRectifyMaxTokens)
+
+					retryGeminiBody, txErr := antigravity.TransformClaudeToGeminiWithOptions(&retryClaudeReq, projectID, mappedModel, transformOpts)
+					if txErr == nil {
+						retryResult, retryErr := s.antigravityRetryLoop(antigravityRetryLoopParams{
+							ctx:             ctx,
+							prefix:          prefix,
+							account:         account,
+							proxyURL:        proxyURL,
+							accessToken:     accessToken,
+							action:          action,
+							body:            retryGeminiBody,
+							c:               c,
+							httpUpstream:    s.httpUpstream,
+							settingService:  s.settingService,
+							accountRepo:     s.accountRepo,
+							handleError:     s.handleUpstreamError,
+							requestedModel:  originalModel,
+							isStickySession: isStickySession,
+							groupID:         0,
+							sessionHash:     "",
+						})
+						if retryErr == nil {
+							retryResp := retryResult.resp
+							if retryResp.StatusCode < 400 {
+								_ = resp.Body.Close()
+								resp = retryResp
+								respBody = nil
+							} else {
+								retryBody, _ := io.ReadAll(io.LimitReader(retryResp.Body, 2<<20))
+								_ = retryResp.Body.Close()
+								respBody = retryBody
+								resp = &http.Response{
+									StatusCode: retryResp.StatusCode,
+									Header:     retryResp.Header.Clone(),
+									Body:       io.NopCloser(bytes.NewReader(retryBody)),
+								}
+							}
+						} else {
+							logger.LegacyPrintf("service.antigravity_gateway", "Antigravity account %d: budget rectifier retry failed: %v", account.ID, retryErr)
+						}
+					}
+				}
+			}
+		}
+
 		// 处理错误响应（重试后仍失败或不触发重试）
 		if resp.StatusCode >= 400 {
 			// 检测 prompt too long 错误，返回特殊错误类型供上层 fallback