fix(acceptance): 为高并发验收启用有界排队

生产同构 Gemini 千请求在真实候选并发饱和后因 queueing disabled 返回 429，同时单台压测机建立千条 WAN TCP 产生连接层 reset。仅对 acceptance 与 acceptance_canary 覆盖为 10000 条、最长 15 分钟的有界等待队列，保留候选原始并发和 RPM/TPM 上限；压测传输强制 HTTP/2 复用连接，避免单源连接风暴。正式 production 策略不变。\n\n验证：acceptance-load 与 runner 定向测试通过，新增生产策略不变和验收队列边界单测；gofmt、bash -n、ShellCheck、git diff --check 通过。

apps/api/internal/runner/admission.go

@@ -32,6 +32,8 @@ const (
 	asyncWorkerCapacityScopeKey = "global"
 	asyncWorkerQueueLimit       = 10000
 	asyncWorkerMaxWaitSeconds   = 24 * 60 * 60
+	acceptanceQueueLimit        = 10000
+	acceptanceQueueMaxWait      = 15 * 60
 )
 
 func distributedAdmissionModelType(modelType string) bool {
@@ -117,6 +119,7 @@ func (s *Service) buildTaskAdmissionPlan(ctx context.Context, task store.Gateway
 				return taskAdmissionPlan{}, err
 			}
 		}
+		scopes = acceptanceAdmissionScopes(task, scopes)
 		hasConcurrentLimit := false
 		for _, scope := range scopes {
 			if scope.ConcurrentLimit > 0 {
@@ -168,6 +171,21 @@ func (s *Service) withAsyncWorkerCapacityScope(ctx context.Context, scopes []sto
 	return out, nil
 }
 
+func acceptanceAdmissionScopes(task store.GatewayTask, scopes []store.AdmissionScope) []store.AdmissionScope {
+	if task.RunMode != "acceptance" && task.RunMode != "acceptance_canary" {
+		return scopes
+	}
+	out := append([]store.AdmissionScope(nil), scopes...)
+	for index := range out {
+		if out[index].ConcurrentLimit <= 0 {
+			continue
+		}
+		out[index].QueueLimit = acceptanceQueueLimit
+		out[index].MaxWaitSeconds = acceptanceQueueMaxWait
+	}
+	return out
+}
+
 func (s *Service) tryTaskAdmission(ctx context.Context, task store.GatewayTask, plan taskAdmissionPlan, waiterID string) (store.TaskAdmissionResult, error) {
 	return s.tryTaskAdmissionWithAdmittedHook(ctx, task, plan, waiterID, nil)
 }
@@ -313,6 +331,7 @@ func (s *Service) ensureCandidateAdmission(
 			return store.TaskAdmissionResult{}, true, err
 		}
 	}
+	scopes = acceptanceAdmissionScopes(task, scopes)
 	hasConcurrentLimit := false
 	for _, scope := range scopes {
 		if scope.ConcurrentLimit > 0 {