fix(acceptance): 隔离容量压测并稳定数据库连接

将协议模拟验收的供应商并发限额与 Worker 容量门禁分离，真实金丝雀继续保留生产限流。readyz 改用关键连接池并预热关键及 River 池，延长生产连接空闲周期，降低跨地域连接抖动。失败 Run 现在可以原子替换且失败报告记录任务数量，避免 validation 之间短暂放开正式流量。\n\n验证：Go 全量测试、go vet、PostgreSQL 集成测试、ShellCheck、迁移安全、发布脚本、pnpm lint/test/build、OpenAPI 无漂移均通过。

apps/api/internal/store/acceptance.go

@@ -209,9 +209,6 @@ FOR UPDATE`, SystemSettingGatewayTrafficMode).Scan(&currentValue); err != nil {
 	if err := json.Unmarshal(currentValue, &current); err != nil {
 		return GatewayTrafficMode{}, err
 	}
-	if normalizeTrafficMode(current.Mode) != "live" {
-		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
-	}
 	run, err := scanAcceptanceRun(tx.QueryRow(ctx, `
 SELECT `+acceptanceRunColumns+`
 FROM gateway_acceptance_runs
@@ -223,6 +220,40 @@ FOR UPDATE`, strings.TrimSpace(runID)))
 	if run.Status != "pending" && run.Status != "failed" {
 		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
 	}
+	switch normalizeTrafficMode(current.Mode) {
+	case "live":
+	case "validation":
+		if current.RunID == "" || current.RunID == run.ID {
+			return GatewayTrafficMode{}, ErrAcceptanceStateConflict
+		}
+		previous, previousErr := scanAcceptanceRun(tx.QueryRow(ctx, `
+SELECT `+acceptanceRunColumns+`
+FROM gateway_acceptance_runs
+WHERE id = $1::uuid
+FOR UPDATE`, current.RunID))
+		if previousErr != nil {
+			return GatewayTrafficMode{}, previousErr
+		}
+		if previous.Status != "failed" ||
+			previous.ReleaseSHA != current.ReleaseSHA ||
+			previous.APIImageDigest != current.APIImageDigest ||
+			previous.WorkerImageDigest != current.WorkerImageDigest {
+			return GatewayTrafficMode{}, ErrAcceptanceStateConflict
+		}
+		var activeTasks int
+		if err := tx.QueryRow(ctx, `
+SELECT count(*)
+FROM gateway_tasks
+WHERE acceptance_run_id = $1::uuid
+  AND status IN ('queued', 'running')`, previous.ID).Scan(&activeTasks); err != nil {
+			return GatewayTrafficMode{}, err
+		}
+		if activeTasks != 0 {
+			return GatewayTrafficMode{}, ErrAcceptanceStateConflict
+		}
+	default:
+		return GatewayTrafficMode{}, ErrAcceptanceStateConflict
+	}
 	next := GatewayTrafficMode{
 		Mode:              "validation",
 		RunID:             run.ID,

apps/api/internal/store/acceptance_integration_test.go

@@ -323,3 +323,77 @@ FROM gateway_tasks`,
 		t.Fatalf("delete acceptance cleanup billing user: %v", err)
 	}
 }
+
+func TestActivateAcceptanceRunAtomicallyReplacesDrainedFailedRun(t *testing.T) {
+	databaseURL := strings.TrimSpace(os.Getenv("AI_GATEWAY_TEST_DATABASE_URL"))
+	if databaseURL == "" {
+		t.Skip("set AI_GATEWAY_TEST_DATABASE_URL to run acceptance traffic integration test")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+	applyOIDCJITTestMigrations(t, ctx, databaseURL)
+	db, err := Connect(ctx, databaseURL)
+	if err != nil {
+		t.Fatalf("connect store: %v", err)
+	}
+	defer db.Close()
+	if _, err := db.pool.Exec(ctx, `
+UPDATE system_settings
+SET value = '{"mode":"live","revision":0}'::jsonb, updated_at = now()
+WHERE setting_key = $1`, SystemSettingGatewayTrafficMode); err != nil {
+		t.Fatalf("reset traffic mode: %v", err)
+	}
+	t.Cleanup(func() {
+		_, _ = db.pool.Exec(context.Background(), `
+UPDATE system_settings
+SET value = '{"mode":"live","revision":0}'::jsonb, updated_at = now()
+WHERE setting_key = $1`, SystemSettingGatewayTrafficMode)
+	})
+
+	createRun := func(releaseCharacter, digestCharacter string) AcceptanceRun {
+		t.Helper()
+		run, createErr := db.CreateAcceptanceRun(ctx, CreateAcceptanceRunInput{
+			ReleaseSHA:        strings.Repeat(releaseCharacter, 40),
+			APIImageDigest:    "sha256:" + strings.Repeat(digestCharacter, 64),
+			WorkerImageDigest: "sha256:" + strings.Repeat(digestCharacter, 64),
+			APIKeyID:          "atomic-replace-api-key",
+			UserID:            "atomic-replace-user",
+			Token:             strings.Repeat("t", 32),
+			EmulatorBaseURL:   "http://acceptance-emulator:8090",
+			CallbackURL:       "http://acceptance-emulator:8090/callbacks",
+			CapacityProfile:   "P24",
+		})
+		if createErr != nil {
+			t.Fatalf("create acceptance run: %v", createErr)
+		}
+		return run
+	}
+
+	previous := createRun("1", "2")
+	firstMode, err := db.ActivateAcceptanceRun(ctx, previous.ID)
+	if err != nil {
+		t.Fatalf("activate previous run: %v", err)
+	}
+	if _, err := db.FinishAcceptanceRun(ctx, FinishAcceptanceRunInput{
+		RunID: previous.ID, Passed: false, FailureReason: "capacity gate failed",
+	}); err != nil {
+		t.Fatalf("fail previous run: %v", err)
+	}
+	nextRun := createRun("3", "4")
+	nextMode, err := db.ActivateAcceptanceRun(ctx, nextRun.ID)
+	if err != nil {
+		t.Fatalf("atomically replace failed run: %v", err)
+	}
+	if firstMode.Mode != "validation" || nextMode.Mode != "validation" ||
+		nextMode.RunID != nextRun.ID || nextMode.Revision != firstMode.Revision+1 {
+		t.Fatalf("unexpected replacement modes: first=%+v next=%+v", firstMode, nextMode)
+	}
+	storedPrevious, err := db.GetAcceptanceRun(ctx, previous.ID)
+	if err != nil || storedPrevious.Status != "failed" {
+		t.Fatalf("previous run changed during replacement: run=%+v err=%v", storedPrevious, err)
+	}
+	storedNext, err := db.GetAcceptanceRun(ctx, nextRun.ID)
+	if err != nil || storedNext.Status != "running" {
+		t.Fatalf("next run was not activated: run=%+v err=%v", storedNext, err)
+	}
+}