test(acceptance): 在单窗口验证厂商额度峰值

厂商额度验收此前复用了多图与超大图容量素材，3 Worker 的下载和预处理使 24 个任务跨越多个固定分钟窗口，无法精确证明 RPM 与 TPM 上限。\n\n额度场景固定使用三张正常尺寸引用图并为每个任务增加唯一 URL 变体，使请求满足视频协议且能在单窗口完成；6、9 图和超大图转换继续由独立视频容量 profile 覆盖。\n\n验证：\n- go test ./cmd/acceptance-load ./internal/acceptanceworkload -count=1\n- go vet ./cmd/acceptance-load ./internal/acceptanceworkload\n- gofmt -l cmd/acceptance-load/main.go cmd/acceptance-load/main_test.go

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

@@ -13,6 +13,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync/atomic"
 	"testing"
 )
@@ -172,11 +173,34 @@ func TestVideoCombinationsProvide128UniqueInputs(t *testing.T) {
 	if len(seen) != 128 {
 		t.Fatalf("unique combinations=%d", len(seen))
 	}
-	if got := requestedVideoCombinationCount(combinations, 144, 0, 1); got != 131 {
+	if got := requestedVideoCombinationCount(combinations, "video-capacity", 144, 0, 1); got != 131 {
 		t.Fatalf("requested combinations=%d, want 131", got)
 	}
 }
 
+func TestVideoProviderQuotaCombinationsUseDistinctNormalSizedImages(t *testing.T) {
+	images := []string{
+		"https://fixtures.example/image-00.png",
+		"https://fixtures.example/image-01.png",
+		"https://fixtures.example/image-02.png",
+		"https://fixtures.example/image-03.png",
+	}
+	combinations := videoProviderQuotaCombinations(images, 24)
+	if got := requestedVideoCombinationCount(combinations, "video-provider-quota", 24, 0, 1); got != 24 {
+		t.Fatalf("quota combinations=%d, want 24", got)
+	}
+	for _, combination := range combinations {
+		if len(combination) != 3 {
+			t.Fatalf("invalid quota combination: %v", combination)
+		}
+		for _, imageURL := range combination {
+			if !strings.Contains(imageURL, "acceptance_quota_variant=") {
+				t.Fatalf("quota image lacks unique variant: %s", imageURL)
+			}
+		}
+	}
+}
+
 func TestGeminiLoadIsSplitAcrossTwoGatewayAPIs(t *testing.T) {
 	output := paddedPNG(256 << 10)
 	encoded := base64.StdEncoding.EncodeToString(output)