fix(openai): preserve pool-mode same-account retries

Avoid recording the generic account-model transient cooldown for pool-mode statuses explicitly configured for same-account retry. This lets the bounded request-local retry budget complete while preserving cooldowns for other statuses and non-pool accounts.

backend/internal/service/openai_account_runtime_block_fastpath.go

@@ -91,7 +91,12 @@ func (s *OpenAIGatewayService) handleOpenAIAccountUpstreamError(ctx context.Cont
 	if shouldDisable && !modelTempMatched {
 		s.BlockAccountScheduling(account, time.Time{}, "upstream_disable")
 	}
-	if !shouldDisable && account.Platform == PlatformOpenAI && account.Type == AccountTypeAPIKey && shouldCooldownOpenAITransientUpstreamError(statusCode, responseBody) {
+	// Pool-mode retryable upstream errors are already bounded by the request-local
+	// same-account retry budget. Recording the generic account+model transient
+	// cooldown here would block the next approved retry before that budget is used.
+	poolModeRetryable := account.IsPoolMode() && account.IsPoolModeRetryableStatus(statusCode)
+	if !shouldDisable && account.Platform == PlatformOpenAI && account.Type == AccountTypeAPIKey &&
+		shouldCooldownOpenAITransientUpstreamError(statusCode, responseBody) && !poolModeRetryable {
 		model := ""
 		if len(canonicalModel) > 0 {
 			model = canonicalModel[0]

backend/internal/service/openai_account_runtime_block_fastpath_test.go

@@ -142,6 +142,89 @@ func TestOpenAIPoolModeTempRule_StopsSameAccountRetryAndIsolatesBlockToModel(t *
 	require.False(t, gateway.isOpenAIAccountRequestRuntimeBlocked(account, "gpt-5.5"))
 }
 
+func TestOpenAIPoolModeRetryable5xx_DoesNotCreateModelTransientBlock(t *testing.T) {
+	repo := &errorPolicyRepoStub{}
+	rateLimitService := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+	gateway := &OpenAIGatewayService{rateLimitService: rateLimitService}
+	account := &Account{
+		ID:       47,
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeAPIKey,
+		Credentials: map[string]any{
+			"pool_mode":                    true,
+			"pool_mode_retry_status_codes": []any{float64(524)},
+		},
+	}
+
+	for i := 0; i < 2; i++ {
+		shouldDisable := gateway.handleOpenAIAccountUpstreamError(
+			context.Background(),
+			account,
+			524,
+			http.Header{},
+			[]byte(`{"error":{"message":"upstream timeout"}}`),
+			"gpt-5.4",
+		)
+		require.False(t, shouldDisable)
+	}
+
+	require.False(t, gateway.isOpenAIAccountRequestRuntimeBlocked(account, "gpt-5.4"))
+}
+
+func TestOpenAIPoolModeNonRetryable5xx_StillCreatesModelTransientBlock(t *testing.T) {
+	repo := &errorPolicyRepoStub{}
+	rateLimitService := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+	gateway := &OpenAIGatewayService{rateLimitService: rateLimitService}
+	account := &Account{
+		ID:       48,
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeAPIKey,
+		Credentials: map[string]any{
+			"pool_mode":                    true,
+			"pool_mode_retry_status_codes": []any{float64(http.StatusGatewayTimeout)},
+		},
+	}
+
+	for i := 0; i < 2; i++ {
+		shouldDisable := gateway.handleOpenAIAccountUpstreamError(
+			context.Background(),
+			account,
+			http.StatusServiceUnavailable,
+			http.Header{},
+			[]byte(`{"error":{"message":"upstream unavailable"}}`),
+			"gpt-5.4",
+		)
+		require.False(t, shouldDisable)
+	}
+
+	require.True(t, gateway.isOpenAIAccountRequestRuntimeBlocked(account, "gpt-5.4"))
+}
+
+func TestOpenAINonPoolAPIKey5xx_StillCreatesModelTransientBlock(t *testing.T) {
+	repo := &errorPolicyRepoStub{}
+	rateLimitService := NewRateLimitService(repo, nil, &config.Config{}, nil, nil)
+	gateway := &OpenAIGatewayService{rateLimitService: rateLimitService}
+	account := &Account{
+		ID:       49,
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeAPIKey,
+	}
+
+	for i := 0; i < 2; i++ {
+		shouldDisable := gateway.handleOpenAIAccountUpstreamError(
+			context.Background(),
+			account,
+			http.StatusGatewayTimeout,
+			http.Header{},
+			[]byte(`{"error":{"message":"upstream timeout"}}`),
+			"gpt-5.4",
+		)
+		require.False(t, shouldDisable)
+	}
+
+	require.True(t, gateway.isOpenAIAccountRequestRuntimeBlocked(account, "gpt-5.4"))
+}
+
 func TestOpenAIModelNotFound_DoesNotRuntimeBlockWholeAccount(t *testing.T) {
 	repo := &modelNotFoundAccountRepoStub{}
 	svc := &OpenAIGatewayService{