fix(grok): avoid pool cooldown on 5xx

backend/internal/service/openai_gateway_grok.go

@@ -1363,7 +1363,7 @@ func (s *OpenAIGatewayService) handleGrokAccountUpstreamError(ctx context.Contex
 	case http.StatusTooManyRequests:
 		// updateGrokUsageSnapshot installs both runtime and durable rate-limit state.
 	default:
-		if statusCode >= 500 {
+		if statusCode >= 500 && !account.IsPoolMode() {
 			s.tempUnscheduleGrok(ctx, account, 2*time.Minute, "grok upstream temporary error")
 		}
 	}

backend/internal/service/openai_gateway_grok_test.go

@@ -2475,6 +2475,43 @@ func TestHandleGrokAccountUpstreamErrorTempUnschedulesNonRateLimitStates(t *test
 	}
 }
 
+func TestHandleGrokAccountUpstreamError5xxRespectsPoolMode(t *testing.T) {
+	t.Run("pool mode keeps scheduling state", func(t *testing.T) {
+		account := &Account{
+			ID:       611,
+			Platform: PlatformGrok,
+			Type:     AccountTypeAPIKey,
+			Credentials: map[string]any{
+				"pool_mode": true,
+			},
+		}
+		repo := &grokQuotaAccountRepo{}
+		svc := &OpenAIGatewayService{accountRepo: repo}
+
+		svc.handleGrokAccountUpstreamError(context.Background(), account, http.StatusBadGateway, nil, nil)
+
+		require.False(t, svc.isOpenAIAccountRuntimeBlocked(account))
+		require.Zero(t, repo.tempUnschedCalls)
+		require.Nil(t, account.TempUnschedulableUntil)
+		require.Empty(t, account.TempUnschedulableReason)
+	})
+
+	t.Run("non-pool mode keeps two minute cooldown", func(t *testing.T) {
+		account := &Account{ID: 612, Platform: PlatformGrok, Type: AccountTypeAPIKey}
+		repo := &grokQuotaAccountRepo{}
+		svc := &OpenAIGatewayService{accountRepo: repo}
+		before := time.Now()
+
+		svc.handleGrokAccountUpstreamError(context.Background(), account, http.StatusBadGateway, nil, nil)
+
+		require.True(t, svc.isOpenAIAccountRuntimeBlocked(account))
+		require.Equal(t, 1, repo.tempUnschedCalls)
+		require.Equal(t, account.ID, repo.lastTempUnschedID)
+		require.Equal(t, "grok upstream temporary error", repo.lastTempUnschedReason)
+		require.WithinDuration(t, before.Add(2*time.Minute), repo.lastTempUnschedUntil, time.Second)
+	})
+}
+
 func TestHandleGrokAccountUpstreamError429SetsRateLimitedFromRetryAfter(t *testing.T) {
 	account := &Account{ID: 61, Platform: PlatformGrok, Type: AccountTypeOAuth}
 	repo := &grokQuotaAccountRepo{}