feat(transcribe): add TranscribeCoachEmptyState and TranscribeDragDemo components

New coach card replaces the icon+sentence empty state in the Transcribe
panel (edit mode). Three-step guide with 5-s SMIL drawing animation in
step 1 only. Animation freezes at the final frame when
prefers-reduced-motion is active. Footer links to Wikipedia Kurrent and
the Richtlinien page open in new tabs with visible '(öffnet in neuem Tab)'
annotations. 34 new i18n keys in de/en/es.

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

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

@@ -0,0 +1,23 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import TranscribeDragDemo from './TranscribeDragDemo.svelte';
+
+afterEach(() => {
+	cleanup();
+});
+
+describe('TranscribeDragDemo', () => {
+	it('renders an SVG with an aria-label describing the animation', async () => {
+		render(TranscribeDragDemo);
+		const svg = page.getByRole('img');
+		await expect.element(svg).toBeInTheDocument();
+		await expect.element(svg).toHaveAttribute('aria-label');
+	});
+
+	it('contains a dashed-border rectangle animation element', async () => {
+		const { container } = render(TranscribeDragDemo);
+		const rect = container.querySelector('rect');
+		expect(rect).not.toBeNull();
+	});
+});