refactor(person): fold year range into section headings, remove standalone stats bar

The floating stats bar was visually disconnected and showed a combined document
count already visible from the per-section badges. Replaced it with a year range
shown inline next to each section heading (e.g. "Gesendete Dokumente · 12 · 1921–1945"),
making the range contextually relevant per direction.

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

frontend/e2e/persons.spec.ts

@@ -125,6 +125,29 @@ test.describe('Person detail — sent and received documents', () => {
 		await expect(page.getByRole('heading', { name: /Empfangene Dokumente/i })).toBeVisible();
 		await page.screenshot({ path: 'test-results/e2e/person-sent-received.png' });
 	});
+
+	test('shows year range next to document count when documents have dates', async ({ page }) => {
+		// Navigate to the first person who has documents with dates
+		await page.goto('/persons');
+		const personLinks = page.locator('a[href^="/persons/"]:not([href="/persons/new"])');
+		const count = await personLinks.count();
+
+		for (let i = 0; i < count; i++) {
+			await page.goto('/persons');
+			await personLinks.nth(i).click();
+			await page.waitForSelector('[data-hydrated]');
+
+			// Check if either section heading has a year range (4 digits)
+			const sentHeading = page.getByRole('heading', { name: /Gesendete Dokumente/i }).locator('..');
+			const hasYearRange = await sentHeading.locator('span').filter({ hasText: /\d{4}/ }).count();
+			if (hasYearRange > 0) {
+				await expect(sentHeading.locator('span').filter({ hasText: /\d{4}/ }).first()).toBeVisible();
+				await page.screenshot({ path: 'test-results/e2e/person-year-range.png' });
+				return;
+			}
+		}
+		// If no person has dated documents, the test is a no-op (year range is optional)
+	});
 });
 
 test.describe('Person detail — conversations link', () => {