test(#123): add Vitest integration tests for SvelteKit load functions

Adds server-project spec files for the four priority routes:
- routes/+page.server (home/search) — happy path, 401 redirect, network error fallback
- routes/documents/[id]/+page.server — happy path, comments fetch failure, 401/403/404
- routes/persons/[id]/+page.server — happy path, partial API failure, 403/404
- routes/admin/+page.server — ADMIN permission gate (none/read-only/undefined/no groups)

All tests run in Node environment with vi.mock() for createApiClient and
$env/dynamic/private. No real network calls; total suite runs in < 1 second.

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

frontend/src/routes/persons/[id]/page.server.spec.ts

@@ -0,0 +1,83 @@
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+import { load } from './+page.server';
+
+vi.mock('$lib/api.server', () => ({ createApiClient: vi.fn() }));
+
+import { createApiClient } from '$lib/api.server';
+
+const mockFetch = vi.fn() as unknown as typeof fetch;
+
+beforeEach(() => vi.clearAllMocks());
+
+// ─── happy path ───────────────────────────────────────────────────────────────
+
+describe('person detail load — happy path', () => {
+	it('returns person, sentDocuments, and receivedDocuments on success', async () => {
+		vi.mocked(createApiClient).mockReturnValue({
+			GET: vi
+				.fn()
+				.mockResolvedValueOnce({
+					response: { ok: true, status: 200 },
+					data: { id: 'p1', firstName: 'Hans', lastName: 'Müller' }
+				})
+				.mockResolvedValueOnce({ response: { ok: true }, data: [{ id: 'd1', title: 'Brief' }] })
+				.mockResolvedValueOnce({ response: { ok: true }, data: [] })
+		} as ReturnType<typeof createApiClient>);
+
+		const result = await load({ params: { id: 'p1' }, fetch: mockFetch });
+
+		expect(result.person.firstName).toBe('Hans');
+		expect(result.sentDocuments).toHaveLength(1);
+		expect(result.receivedDocuments).toEqual([]);
+	});
+
+	it('returns empty arrays when sent/received document APIs fail', async () => {
+		vi.mocked(createApiClient).mockReturnValue({
+			GET: vi
+				.fn()
+				.mockResolvedValueOnce({
+					response: { ok: true, status: 200 },
+					data: { id: 'p1', firstName: 'Anna', lastName: 'Schmidt' }
+				})
+				.mockResolvedValueOnce({ response: { ok: false }, data: null })
+				.mockResolvedValueOnce({ response: { ok: false }, data: null })
+		} as ReturnType<typeof createApiClient>);
+
+		const result = await load({ params: { id: 'p1' }, fetch: mockFetch });
+
+		expect(result.sentDocuments).toEqual([]);
+		expect(result.receivedDocuments).toEqual([]);
+	});
+});
+
+// ─── error paths ──────────────────────────────────────────────────────────────
+
+describe('person detail load — error paths', () => {
+	it('throws 404 when person does not exist', async () => {
+		vi.mocked(createApiClient).mockReturnValue({
+			GET: vi
+				.fn()
+				.mockResolvedValueOnce({ response: { ok: false, status: 404 }, error: null })
+				.mockResolvedValueOnce({ response: { ok: true }, data: [] })
+				.mockResolvedValueOnce({ response: { ok: true }, data: [] })
+		} as ReturnType<typeof createApiClient>);
+
+		await expect(load({ params: { id: 'missing' }, fetch: mockFetch })).rejects.toMatchObject({
+			status: 404
+		});
+	});
+
+	it('throws 403 when person is not accessible', async () => {
+		vi.mocked(createApiClient).mockReturnValue({
+			GET: vi
+				.fn()
+				.mockResolvedValueOnce({ response: { ok: false, status: 403 }, error: null })
+				.mockResolvedValueOnce({ response: { ok: true }, data: [] })
+				.mockResolvedValueOnce({ response: { ok: true }, data: [] })
+		} as ReturnType<typeof createApiClient>);
+
+		await expect(load({ params: { id: 'forbidden' }, fetch: mockFetch })).rejects.toMatchObject({
+			status: 403
+		});
+	});
+});