fix(geschichte): raise journey reading text to the accessibility floor

Intro, letter titles, curator annotations, and interludes rendered at
12-14px — copied from the scaled mockup sizes in LR-2. Narrative text
is now 16-18px, meta lines and links 14px; the LR-2 impl-ref table is
updated to match.

Closes #800
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/lib/geschichte/JourneyReader.svelte.spec.ts

@@ -62,6 +62,17 @@ describe('JourneyReader', () => {
 		await expect.element(page.getByText('Eine Reise durch die Geschichte.')).toBeVisible();
 	});
 
+	it('intro paragraph uses readable body size (text-lg, #800)', async () => {
+		render(JourneyReader, {
+			context: ctx(),
+			props: { geschichte: baseGeschichte({ body: 'Eine Reise durch die Geschichte.' }) }
+		});
+
+		const intro = document.querySelector('p');
+		expect(intro!.className).toContain('text-lg');
+		expect(intro!.className).not.toContain('text-sm');
+	});
+
 	it('omits intro paragraph when body is null', async () => {
 		render(JourneyReader, {
 			context: ctx(),