fix(acceptance): 解除八任务准入瓶颈

线上 P24 验收证明 Worker 注册容量为 48，但异步 admission 始终只有 8 条活跃租约。将单事务调度窗口覆盖当前 2 x P32 的 64 槽，避免多 Worker 在同一 FIFO 小批次上竞争形成隐性全局上限。\n\nGemini 流式请求补充可回放 GetBody 与精确 Content-Length，使带幂等键的 POST 遇到 HTTP/2 可重试传输错误时可安全重放；同时提前部署验收回调收集器，保证旧 Run side effects 能在接管前收口。\n\n已通过 Go 全量测试、go vet、gofmt、Shell bash -n、ShellCheck、验收与人工发布脚本测试、迁移安全检查，以及独立 PostgreSQL 48 条 admission/租约/River job 原子集成测试。

apps/api/internal/store/admission_queue_integration_test.go

@@ -506,13 +506,16 @@ WHERE id = $1::uuid`, recoveryGraceTask.ID); err != nil {
 		ScopeType:       "worker_capacity",
 		ScopeKey:        "batch-" + suffix,
 		ScopeName:       "batch capacity",
-		ConcurrentLimit: 3,
+		ConcurrentLimit: 48,
 		Amount:          1,
 		LeaseTTLSeconds: 120,
 		QueueLimit:      100,
 		MaxWaitSeconds:  600,
 	}
-	batchTasks := []GatewayTask{createTask(true), createTask(true), createTask(true)}
+	batchTasks := make([]GatewayTask, 48)
+	for index := range batchTasks {
+		batchTasks[index] = createTask(true)
+	}
 	batchInputs := make([]TaskAdmissionInput, 0, len(batchTasks))
 	batchJobIDs := make(map[string]int64, len(batchTasks))
 	for index, task := range batchTasks {
@@ -544,6 +547,10 @@ WHERE id = $1::uuid`, input.TaskID, batchJobIDs[input.TaskID])
 			t.Fatalf("batch outcome %d=%+v", index, outcome)
 		}
 	}
+	batchTaskIDs := make([]string, 0, len(batchTasks))
+	for _, task := range batchTasks {
+		batchTaskIDs = append(batchTaskIDs, task.ID)
+	}
 	var batchAdmissions, batchLeases, batchRiverJobs int
 	if err := first.pool.QueryRow(ctx, `
 SELECT
@@ -556,16 +563,19 @@ SELECT
   (SELECT count(*)
    FROM gateway_tasks
    WHERE id = ANY($1::uuid[]) AND river_job_id IS NOT NULL)`,
-		[]string{batchTasks[0].ID, batchTasks[1].ID, batchTasks[2].ID},
+		batchTaskIDs,
 	).Scan(&batchAdmissions, &batchLeases, &batchRiverJobs); err != nil {
 		t.Fatalf("read committed batch admission: %v", err)
 	}
-	if batchAdmissions != 3 || batchLeases != 3 || batchRiverJobs != 3 {
+	if batchAdmissions != len(batchTasks) || batchLeases != len(batchTasks) || batchRiverJobs != len(batchTasks) {
 		t.Fatalf(
-			"batch admissions=%d leases=%d River jobs=%d, want 3/3/3",
+			"batch admissions=%d leases=%d River jobs=%d, want %d/%d/%d",
 			batchAdmissions,
 			batchLeases,
 			batchRiverJobs,
+			len(batchTasks),
+			len(batchTasks),
+			len(batchTasks),
 		)
 	}
 	for _, task := range batchTasks {