feat(ocr): add OcrProgressBar component with page-based ARIA semantics

Progress bar shows brand-mint fill on brand-sand background with
smooth transition. Displays page counter with tabular-nums and
skipped-pages warning in amber when applicable. Only renders when
totalPages > 0.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/OcrProgressBar.svelte

@@ -0,0 +1,39 @@
+<script lang="ts">
+let {
+	currentPage,
+	totalPages,
+	skippedPages = 0
+}: {
+	currentPage: number;
+	totalPages: number;
+	skippedPages?: number;
+} = $props();
+
+let percentage = $derived((currentPage / totalPages) * 100);
+</script>
+
+{#if totalPages > 0}
+	<div class="flex flex-col items-center">
+		<div
+			class="bg-brand-sand mx-auto mt-4 h-2 w-full max-w-xs rounded-full"
+			role="progressbar"
+			aria-valuenow={currentPage}
+			aria-valuemax={totalPages}
+			aria-label="OCR progress"
+		>
+			<div
+				class="h-full rounded-full bg-brand-mint transition-all duration-500"
+				data-testid="progress-fill"
+				style="width: {percentage}%"
+			></div>
+		</div>
+		<span class="mt-1 text-xs text-gray-400 tabular-nums">
+			{currentPage} / {totalPages}
+		</span>
+		{#if skippedPages > 0}
+			<span class="mt-1 text-xs text-amber-600" data-testid="skipped-warning">
+				{skippedPages} Seiten übersprungen
+			</span>
+		{/if}
+	</div>
+{/if}

frontend/src/lib/components/OcrProgressBar.svelte.spec.ts

@@ -0,0 +1,43 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import OcrProgressBar from './OcrProgressBar.svelte';
+
+afterEach(cleanup);
+
+describe('OcrProgressBar', () => {
+	it('renders progress bar with correct ARIA attributes', async () => {
+		render(OcrProgressBar, { currentPage: 2, totalPages: 5 });
+		const bar = page.getByRole('progressbar');
+		await expect.element(bar).toHaveAttribute('aria-valuenow', '2');
+		await expect.element(bar).toHaveAttribute('aria-valuemax', '5');
+	});
+
+	it('hides progress bar when totalPages is zero', async () => {
+		render(OcrProgressBar, { currentPage: 0, totalPages: 0 });
+		await expect.element(page.getByRole('progressbar')).not.toBeInTheDocument();
+	});
+
+	it('fills to 100 percent when current equals total', async () => {
+		render(OcrProgressBar, { currentPage: 5, totalPages: 5 });
+		const fill = page.getByTestId('progress-fill');
+		await expect.element(fill).toBeInTheDocument();
+		const el = fill.element() as HTMLElement;
+		expect(el.style.width).toBe('100%');
+	});
+
+	it('shows page counter text', async () => {
+		render(OcrProgressBar, { currentPage: 3, totalPages: 7 });
+		await expect.element(page.getByText('3 / 7')).toBeInTheDocument();
+	});
+
+	it('shows skipped pages warning when skippedPages > 0', async () => {
+		render(OcrProgressBar, { currentPage: 5, totalPages: 5, skippedPages: 2 });
+		await expect.element(page.getByTestId('skipped-warning')).toBeInTheDocument();
+	});
+
+	it('does not show warning when skippedPages is 0', async () => {
+		render(OcrProgressBar, { currentPage: 3, totalPages: 5, skippedPages: 0 });
+		await expect.element(page.getByTestId('skipped-warning')).not.toBeInTheDocument();
+	});
+});