test(acceptance): 增加视频容量阶梯场景

新增 30 至 45 秒模拟上游等待的视频容量场景，使单 Worker 自适应控制在每级突发负载中获得连续占满窗口，同时保持提交、轮询、结果处理和回调全链路。\n\n未修改生产 Worker 和厂商限流逻辑。已执行完整 Go 测试、go vet、gofmt、bash -n、ShellCheck 和生产验收脚本测试。

apps/api/cmd/acceptance-load/main.go

@@ -279,7 +279,7 @@ func parseOptions() (options, error) {
 		return options{}, errors.New("requests must be between 0 and 10000")
 	}
 	switch opts.profile {
-	case "simulated-smoke", "simulated-all", "gemini-baseline", "gemini-multi-image", "gemini-large", "gemini-peak", "video-throughput", "video-recovery",
+	case "simulated-smoke", "simulated-all", "gemini-baseline", "gemini-multi-image", "gemini-large", "gemini-peak", "video-throughput", "video-capacity", "video-recovery",
 		"mixed-soak", "mixed-overload":
 		if opts.emulatorURL == "" {
 			return options{}, errors.New("AI_GATEWAY_ACCEPTANCE_EMULATOR_URL is required for simulated profiles")
@@ -365,6 +365,12 @@ func run(ctx context.Context, opts options) ([]phaseResult, error) {
 					requests = opts.requestCount
 				}
 				result = runVideo(ctx, client, opts, name, opts.shardRequestCount(requests), false, opts.emulatorFixtureURLs(), false, opts.shardIndex, opts.shardCount)
+			case "video-capacity":
+				requests := 1200
+				if opts.requestCount > 0 {
+					requests = opts.requestCount
+				}
+				result = runVideo(ctx, client, opts, name, opts.shardRequestCount(requests), false, opts.emulatorFixtureURLs(), false, opts.shardIndex, opts.shardCount)
 			case "video-recovery":
 				result = runVideo(ctx, client, opts, name, opts.shardRequestCount(96), true, opts.emulatorFixtureURLs(), false, opts.shardIndex, opts.shardCount)
 			case "mixed-soak", "mixed-overload":
@@ -659,6 +665,9 @@ func runVideo(
 			if longRun {
 				prompt += " acceptance-long-recovery"
 			}
+			if name == "video-capacity" {
+				prompt += " acceptance-capacity-ladder"
+			}
 			if !realUpstream && logicalIndex%4 == 0 {
 				prompt += " acceptance-force-conversion"
 			}