fix(a11y): bump progress bar text to text-xs minimum, add motion-safe to upload animation

- text-[9px]/text-[10px] in required-fields bar raised to text-xs (12px),
  meeting the project minimum for the 60+ audience (WCAG 1.4.4)
- Upload animation now uses motion-safe: prefix so it stops for users
  with prefers-reduced-motion set (WCAG 2.1 SC 2.3.3)
- Strengthened UploadZone tests: onCancel uses [role=status] button
  selector instead of first-button heuristic; added positive file
  selection test (valid PDF calls onFile), file-too-large test, and
  MIME rejection now also asserts the error message is visible

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/components/document/UploadZone.svelte

@@ -55,7 +55,9 @@ function handleDrop(e: DragEvent) {
 	{#if isUploading}
 		<div role="status" class="flex flex-col items-center gap-3 text-center">
 			<div class="h-0.5 w-48 overflow-hidden rounded-full bg-white/10">
-				<div class="h-full animate-[slide_1.4s_ease-in-out_infinite] bg-brand-mint/70"></div>
+				<div
+					class="h-full bg-brand-mint/70 motion-safe:animate-[slide_1.4s_ease-in-out_infinite]"
+				></div>
 			</div>
 			<p class="max-w-[200px] truncate text-xs font-medium text-brand-mint/70">{filename}</p>
 			<p class="text-xs text-white/40">Wird hochgeladen …</p>

frontend/src/lib/components/document/UploadZone.svelte.test.ts

@@ -47,7 +47,8 @@ describe('UploadZone', () => {
 			render(UploadZone, {
 				props: { filename: 'scan.pdf', isUploading: true, isDragging: false, error: null, onCancel }
 			});
-			const btn = document.querySelector('button')!;
+			// Click the button inside [role="status"] — more specific than querySelector('button')
+			const btn = document.querySelector('[role="status"] button') as HTMLButtonElement;
 			btn.dispatchEvent(new MouseEvent('click', { bubbles: true }));
 			expect(onCancel).toHaveBeenCalledOnce();
 		});
@@ -68,6 +69,18 @@ describe('UploadZone', () => {
 	});
 
 	describe('file selection', () => {
+		it('calls onFile for a valid PDF', () => {
+			const onFile = vi.fn();
+			render(UploadZone, {
+				props: { filename: 'scan.pdf', isUploading: false, isDragging: false, error: null, onFile }
+			});
+			const input = document.querySelector('input[type="file"]') as HTMLInputElement;
+			const pdf = new File(['%PDF-1.4'], 'brief.pdf', { type: 'application/pdf' });
+			Object.defineProperty(input, 'files', { value: [pdf], writable: false });
+			input.dispatchEvent(new Event('change', { bubbles: true }));
+			expect(onFile).toHaveBeenCalledWith(pdf);
+		});
+
 		it('does not call onFile for an unsupported MIME type', async () => {
 			const onFile = vi.fn();
 			render(UploadZone, {
@@ -80,6 +93,23 @@ describe('UploadZone', () => {
 			Object.defineProperty(input, 'files', { value: [docxFile], writable: false });
 			input.dispatchEvent(new Event('change', { bubbles: true }));
 			expect(onFile).not.toHaveBeenCalled();
+			await expect
+				.element(page.getByText('Dieser Dateityp wird nicht unterstützt (PDF, JPG, PNG, TIFF).'))
+				.toBeVisible();
+		});
+
+		it('does not call onFile when file exceeds 50 MB', async () => {
+			const onFile = vi.fn();
+			render(UploadZone, {
+				props: { filename: 'scan.pdf', isUploading: false, isDragging: false, error: null, onFile }
+			});
+			const input = document.querySelector('input[type="file"]') as HTMLInputElement;
+			const bigFile = new File(['x'.repeat(1)], 'huge.pdf', { type: 'application/pdf' });
+			Object.defineProperty(bigFile, 'size', { value: 51 * 1024 * 1024 });
+			Object.defineProperty(input, 'files', { value: [bigFile], writable: false });
+			input.dispatchEvent(new Event('change', { bubbles: true }));
+			expect(onFile).not.toHaveBeenCalled();
+			await expect.element(page.getByText('Die Datei ist zu groß (max. 50 MB).')).toBeVisible();
 		});
 	});
 });

frontend/src/routes/enrich/[id]/+page.svelte

@@ -120,7 +120,7 @@ async function handleReplaceFile(e: Event) {
 
 	<!-- Required-fields progress bar -->
 	<div class="flex items-center gap-3 border-b border-line bg-surface px-6 py-1.5">
-		<span class="text-[9px] font-bold tracking-widest text-ink-3 uppercase">Pflichtfelder</span>
+		<span class="text-xs font-bold tracking-widest text-ink-3 uppercase">Pflichtfelder</span>
 		<div
 			class="h-0.5 flex-1 rounded-full bg-line"
 			role="progressbar"
@@ -134,7 +134,7 @@ async function handleReplaceFile(e: Event) {
 				style="width:{requiredPct}%"
 			></div>
 		</div>
-		<span class="text-[10px] font-bold text-brand-navy">{requiredFilled} / 3</span>
+		<span class="text-xs font-bold text-brand-navy">{requiredFilled} / 3</span>
 	</div>
 
 	<!-- Main content -->