The git changes introduce functionality to merge attachments from a processed ZIP archive into a single PDF file. Here is a summary of the changes: ### New Features - PDF Merging: Added the ability to merge multiple attachments (PDFs and images) from a processed ZIP archive into a single PDF document. - Image Conversion: Implemented automatic conversion of non-PNG images (like JPGs) to PNG format before embedding them into the merged PDF. ### File Changes - Dependencies: Added pdf-lib to the project's dependencies. - src/lib/zip-processing.ts:

- Added mergeProcessedZipArchive to handle the core logic of creating a merged PDF.                         - Implemented helpers to embed PDF pages and convert/embed images.     - Added toArrayBuffer and convertImageBytesToPng utilities for handling binary data and canvas-based image processing.
     - src/lib/components/ProcessedZipArchiveEditor.svelte:
 - Added a "PDF herunterladen" (Download PDF) button.              - Added UI states to handle the merging process (loading state, error messages).
     - Integrated the mergeProcessedZipArchive function with the UI.
      - src/lib/components/AttachmentPreview.svelte:
 - Added a fix to ensure attachment.data is treated as a Uint8Array when loading PDF documents.

src/lib/components/ProcessedZipArchiveEditor.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
     import AttachmentPreview from "$lib/components/AttachmentPreview.svelte";
-    import type {ProcessedZipArchive, ZipAttachment} from "$lib/zip-processing";
+    import { mergeProcessedZipArchive, type ProcessedZipArchive, type ZipAttachment } from "$lib/zip-processing";
 
     type Props = {
         archive: ProcessedZipArchive;
@@ -19,6 +19,14 @@
     let archiveName = $state("");
     let dragIndex = $state<number | null>(null);
     let dropIndex = $state<number | null>(null);
+    let isMerging = $state(false);
+    let mergeError = $state<string | null>(null);
+
+    const toArrayBuffer = (bytes: Uint8Array) => {
+        const copy = new Uint8Array(bytes.byteLength);
+        copy.set(bytes);
+        return copy.buffer;
+    };
 
     $effect(() => {
         archiveName = archive.name;
@@ -33,6 +41,37 @@
         });
     };
 
+    const downloadMergedPdf = async () => {
+        if (attachments.length === 0 || isMerging) {
+            return;
+        }
+
+        isMerging = true;
+        mergeError = null;
+
+        try {
+            const mergedBytes = await mergeProcessedZipArchive({
+                ...archive,
+                name: archiveName,
+                attachments: attachments.map((attachment) => ({...attachment}))
+            });
+
+            const pdfBlob = new Blob([toArrayBuffer(mergedBytes)], {type: "application/pdf"});
+            const objectUrl = URL.createObjectURL(pdfBlob);
+            const downloadLink = document.createElement("a");
+            downloadLink.href = objectUrl;
+            downloadLink.download = archiveName.toLowerCase().endsWith(".pdf") ? archiveName : `${archiveName}.pdf`;
+            downloadLink.rel = "noopener";
+            downloadLink.click();
+            window.setTimeout(() => URL.revokeObjectURL(objectUrl), 1000);
+        } catch (error) {
+            console.error(`Failed to merge archive ${archive.name}`, error);
+            mergeError = "PDF konnte nicht erstellt werden.";
+        } finally {
+            isMerging = false;
+        }
+    };
+
     const moveAttachment = (fromIndex: number, toIndex: number) => {
         if (
             fromIndex === toIndex ||
@@ -107,8 +146,23 @@
                 {attachments.length} relevante Datei{attachments.length === 1 ? "" : "en"}
             </p>
         </div>
+
+        <button
+                class="rounded-container whitespace-nowrap bg-primary-900 px-4 py-2 text-[14px] font-bold leading-6 text-white shadow-sm transition hover:bg-primary-800 disabled:cursor-not-allowed disabled:bg-primary-300"
+                type="button"
+                disabled={attachments.length === 0 || isMerging}
+                onclick={downloadMergedPdf}
+        >
+            {isMerging ? "PDF wird erstellt" : "PDF herunterladen"}
+        </button>
     </header>
 
+    {#if mergeError}
+        <div class="rounded-container bg-red-50 px-4 py-3 text-[14px] font-medium text-red-900">
+            {mergeError}
+        </div>
+    {/if}
+
     <ul class="flex gap-3 overflow-x-auto pb-1">
         {#each attachments as attachment, index (attachment.path)}
             <li