test(e2e): add coverage for all 12 critical journeys (TEST-3 #405)

Adds docs/audits/e2e-coverage-report.md mapping all 12 critical journeys
to their test files. Fills the 6 coverage gaps with new e2e tests:

- J1: Register via invite code (auth.spec.ts)
- J3: Edit document tags via TagInput (documents.spec.ts)
- J4: Create brand-new tag via TagInput (documents.spec.ts)
- J5: Add SPOUSE_OF relationship on person edit page (persons.spec.ts)
- J6: Multi-filter search (text + date, text + tagId) (documents.spec.ts)
- J10: Notification bell opens dropdown (notification-deep-link.spec.ts)
- J11: Non-admin blocked from /admin/* (permissions.spec.ts)
- J12: Mass import trigger shows status (admin.spec.ts)

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

frontend/e2e/admin.spec.ts

@@ -217,6 +217,32 @@ test.describe('Admin — tag management', () => {
 	});
 });
 
+// ─── System tab — mass import trigger (J12) ───────────────────────────────────
+
+test.describe('Admin system tab — mass import trigger', () => {
+	test('admin triggers mass import and sees a status response', async ({ page }) => {
+		test.setTimeout(30_000);
+
+		await page.goto('/admin');
+		await page.waitForSelector('[data-hydrated]');
+
+		await page.getByRole('button', { name: /system/i }).click();
+
+		// The import button is rendered as [data-import-trigger] in all states.
+		const importBtn = page.locator('[data-import-trigger]');
+		await expect(importBtn.first()).toBeVisible({ timeout: 10_000 });
+		await importBtn.first().click();
+
+		// After triggering, either a RUNNING status text appears (job started)
+		// or a DONE/FAILED result text appears (job finished quickly or was already done).
+		await expect(
+			page.locator('text=/Importiert|Dokument|Import|Läuft|DONE|laufend/i').first()
+		).toBeVisible({ timeout: 15_000 });
+
+		await page.screenshot({ path: 'test-results/e2e/admin-mass-import-triggered.png' });
+	});
+});
+
 // ─── System tab — backfill file hashes ────────────────────────────────────────
 
 test.describe('Admin system tab — backfill file hashes', () => {