perf(worker): 隔离异步等待登记与执行锁

为异步等待队列登记增加独立的进程内和 PostgreSQL advisory lock 域，使严格队列上限校验不再等待 Worker 执行槽事务的跨城同步提交。任务级锁保持不变，调度期间 active 与 waiting 总量守恒。\n\n新增 PostgreSQL 集成测试，验证执行 scope 锁被占用时等待登记仍可独立完成。\n\n验证：go vet ./...；go test ./... -count=1；隔离 PostgreSQL 集成测试；迁移安全检查；gofmt；git diff --check。

apps/api/internal/store/admission_lock.go

@@ -114,6 +114,14 @@ func admissionOperationLockKeys(input TaskAdmissionInput) []string {
 	return normalizedAdmissionLockKeys(keys)
 }
 
+func queuedAdmissionOperationLockKeys(input TaskAdmissionInput) []string {
+	keys := []string{"task-admission:" + input.TaskID}
+	for _, scope := range normalizedAdmissionScopes(input.Scopes) {
+		keys = append(keys, admissionQueueRegistrationLockKey(scope))
+	}
+	return normalizedAdmissionLockKeys(keys)
+}
+
 func tryAdmissionTransactionLock(ctx context.Context, tx pgx.Tx, key string) error {
 	// The process-local lock limits this wait to one PostgreSQL connection per
 	// API or Worker process. Let PostgreSQL queue those process representatives