feat(preview): add archive listing and browser support

Introduces the ability to browse and preview the contents of archive files directly within the web interface.

Changes include:
- Added a new API endpoint `GET /d/{boxID}/archive/{fileID}` to fetch archive listings.
- Implemented on-demand archive listing generation in the backend.
- Updated the frontend preview component to support rendering and navigating archive contents.

backend/libs/jobs/thumbnails_test.go

@@ -1,7 +1,9 @@
 package jobs
 
 import (
+	"archive/zip"
 	"bytes"
+	"encoding/json"
 	"image"
 	"image/color"
 	"image/jpeg"
@@ -108,6 +110,51 @@ func TestRenderVideoScenesThumbnailReturnsLargeJPEG(t *testing.T) {
 	}
 }
 
+func TestCreateArchiveListingRendersZipTree(t *testing.T) {
+	var archive bytes.Buffer
+	writer := zip.NewWriter(&archive)
+	addZipTestFile(t, writer, "docs/readme.md", "hello")
+	addZipTestFile(t, writer, "src/main.go", "package main\n")
+	if err := writer.Close(); err != nil {
+		t.Fatalf("zip.Close returned error: %v", err)
+	}
+
+	data, err := createArchiveListing(services.File{Name: "bundle.zip", ContentType: "application/zip"}, bytes.NewReader(archive.Bytes()))
+	if err != nil {
+		t.Fatalf("createArchiveListing returned error: %v", err)
+	}
+	var listing archiveListingData
+	if err := json.Unmarshal(data, &listing); err != nil {
+		t.Fatalf("json.Unmarshal returned error: %v\n%s", err, string(data))
+	}
+	if listing.Name != "bundle.zip" || listing.FileCount != 2 || listing.FolderCount != 2 {
+		t.Fatalf("archive listing metadata = %+v", listing)
+	}
+	if listing.Root == nil || len(listing.Root.Items) != 2 {
+		t.Fatalf("archive listing root = %+v", listing.Root)
+	}
+	if listing.Root.Items[0].Name != "docs" || listing.Root.Items[0].Icon != "folder" {
+		t.Fatalf("first archive folder = %+v", listing.Root.Items[0])
+	}
+	if listing.Root.Items[0].Items[0].Name != "readme.md" || listing.Root.Items[0].Items[0].Icon != "txt" {
+		t.Fatalf("markdown archive file = %+v", listing.Root.Items[0].Items[0])
+	}
+	if listing.Root.Items[1].Items[0].Name != "main.go" || listing.Root.Items[1].Items[0].Icon != "code" {
+		t.Fatalf("go archive file = %+v", listing.Root.Items[1].Items[0])
+	}
+}
+
+func addZipTestFile(t *testing.T, writer *zip.Writer, name, body string) {
+	t.Helper()
+	file, err := writer.Create(name)
+	if err != nil {
+		t.Fatalf("zip.Create returned error: %v", err)
+	}
+	if _, err := file.Write([]byte(body)); err != nil {
+		t.Fatalf("zip file write returned error: %v", err)
+	}
+}
+
 func solidTestImage(c color.Color) image.Image {
 	img := image.NewRGBA(image.Rect(0, 0, 32, 24))
 	for y := 0; y < img.Bounds().Dy(); y++ {