feat(media): 素材删除 - 安全清理未引用的存储资源

删除素材前检查项目、画布、任务、其他素材、工作流、风格和声音引用；仅清理未复用的本地或 OSS/COS 对象。

backend/internal/service/resource_delete_test.go

@@ -0,0 +1,80 @@
+package service
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestCollectOwnedAssetDocumentReferences(t *testing.T) {
+	resources := map[string]struct{}{}
+	tasks := map[string]struct{}{}
+	raw := `{
+		"data":{"storageKey":"resource:resource-1","url":"/api/resources/resource-2/file"},
+		"metadata":{"taskId":"task-1","referenceResourceIds":["resource-3"],"errorDetails":"failed near /api/resources/not-a-reference/file"}
+	}`
+	if err := collectOwnedAssetDocumentReferences(raw, resources, tasks); err != nil {
+		t.Fatal(err)
+	}
+	for _, resourceID := range []string{"resource-1", "resource-2", "resource-3"} {
+		if _, exists := resources[resourceID]; !exists {
+			t.Fatalf("resource %q was not collected: %#v", resourceID, resources)
+		}
+	}
+	if _, exists := tasks["task-1"]; !exists {
+		t.Fatalf("origin task was not collected: %#v", tasks)
+	}
+	if _, exists := resources["not-a-reference"]; exists {
+		t.Fatalf("diagnostic text must not be treated as an actual resource reference: %#v", resources)
+	}
+}
+
+func TestDocumentReferencesResourcesUsesExactResourceID(t *testing.T) {
+	candidates := map[string]struct{}{"resource-1": {}}
+	if documentReferencesResources(`{"storageKey":"resource:resource-10"}`, candidates) {
+		t.Fatal("resource-1 must not match resource-10")
+	}
+	if !documentReferencesResources(`{"storageKey":"resource:resource-1"}`, candidates) {
+		t.Fatal("exact resource ID should match")
+	}
+}
+
+func TestResourceOccupiedMessageNamesBusinessRecord(t *testing.T) {
+	message := resourceOccupiedMessage([]resourceUsage{
+		{Kind: "画布", ID: "canvas-1", Title: "广告分镜"},
+		{Kind: "画布", ID: "canvas-1", Title: "广告分镜"},
+	})
+	if !strings.Contains(message, "画布「广告分镜」") || !strings.Contains(message, "解除引用") {
+		t.Fatalf("message = %q", message)
+	}
+}
+
+func TestDeleteLocalResourceObjectRemovesOnlyResourceDirectoryFile(t *testing.T) {
+	dataDir := t.TempDir()
+	resourcePath := filepath.Join(dataDir, "resources", "users", "user-1", "image", "asset.png")
+	if err := os.MkdirAll(filepath.Dir(resourcePath), 0o750); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(resourcePath, []byte("image"), 0o640); err != nil {
+		t.Fatal(err)
+	}
+	service := &Service{dataDir: dataDir}
+	if err := service.deleteLocalResourceObject("users/user-1/image/asset.png"); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(resourcePath); !os.IsNotExist(err) {
+		t.Fatalf("resource file still exists or stat failed unexpectedly: %v", err)
+	}
+
+	outsidePath := filepath.Join(dataDir, "outside.txt")
+	if err := os.WriteFile(outsidePath, []byte("keep"), 0o640); err != nil {
+		t.Fatal(err)
+	}
+	if err := service.deleteLocalResourceObject("../outside.txt"); err == nil {
+		t.Fatal("path traversal should be rejected")
+	}
+	if _, err := os.Stat(outsidePath); err != nil {
+		t.Fatalf("outside file was changed: %v", err)
+	}
+}