feat(delivery): replace deliveryEditorSlice with automat and add PDF/text attachment handling

- replace Redux deliveryEditorSlice with deliveryEditorAutomat using automat
- add Attachment and AttachmentList components in Kopfdaten
- extract PDF text via pdftotext-wasm and render PDF thumbnails with pdfjs-dist
- add TextEditorDialog to view and edit extracted text files (preformatted monospace, no wrap)
- configure Vite server.fs.allow for pdftotext.wasm

src/utils/pdfThumbnail.js

@@ -0,0 +1,36 @@
+import * as pdfjsLib from 'pdfjs-dist';
+
+// Tells Vite/Webpack to emit the worker script as an asset file locally
+pdfjsLib.GlobalWorkerOptions.workerSrc = new URL(
+  'pdfjs-dist/build/pdf.worker.mjs',
+  import.meta.url
+).toString();
+
+export async function generatePdfThumbnail(pdfSource, targetWidth = 200) {
+  let loadingTask;
+  if (pdfSource instanceof File || pdfSource instanceof Blob) {
+    const arrayBuffer = await pdfSource.arrayBuffer();
+    loadingTask = pdfjsLib.getDocument({ data: arrayBuffer });
+  } else {
+    loadingTask = pdfjsLib.getDocument(pdfSource);
+  }
+
+  const pdf = await loadingTask.promise;
+  const page = await pdf.getPage(1);
+
+  const unscaledViewport = page.getViewport({ scale: 1 });
+  const scale = targetWidth / unscaledViewport.width;
+  const viewport = page.getViewport({ scale });
+
+  const canvas = document.createElement('canvas');
+  const context = canvas.getContext('2d');
+  canvas.width = Math.floor(viewport.width);
+  canvas.height = Math.floor(viewport.height);
+
+  await page.render({
+    canvasContext: context,
+    viewport: viewport,
+  }).promise;
+
+  return canvas.toDataURL('image/jpeg', 0.85);
+}