refactor: move lib-root files to lib/shared/ and finalize domain structure

- Move api.server.ts, errors.ts, types.ts, utils.ts, relativeTime.ts to lib/shared/
- Move person relationship components to lib/person/relationship/
- Move Stammbaum components to lib/person/genealogy/
- Move HelpPopover to lib/shared/primitives/
- Update all import paths across routes, specs, and lib files
- Update vi.mock() paths in server-project test files
- Remove now-empty legacy directories (components/, hooks/, server/, etc.)
- Update vite.config.ts coverage include paths for new structure
- Update frontend/CLAUDE.md to reflect domain-based lib/ layout

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

frontend/src/lib/person/genealogy/StammbaumSidePanel.svelte.spec.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect, afterEach, vi, beforeEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import StammbaumSidePanel from './StammbaumSidePanel.svelte';
+
+vi.mock('$app/navigation', () => ({ invalidateAll: vi.fn() }));
+vi.mock('$app/forms', () => ({ enhance: () => () => {} }));
+vi.mock('$lib/person/PersonTypeahead.svelte', () => ({ default: () => null }));
+
+const makeNode = () => ({
+	id: 'person-1',
+	displayName: 'Alice Müller',
+	birthYear: 1900,
+	deathYear: null,
+	familyMember: true
+});
+
+function stubFetch(directRels: unknown[] = [], inferredRels: unknown[] = []) {
+	let callCount = 0;
+	vi.stubGlobal(
+		'fetch',
+		vi.fn().mockImplementation(() => {
+			callCount++;
+			const body = callCount % 2 === 1 ? directRels : inferredRels;
+			return Promise.resolve({ ok: true, json: () => Promise.resolve(body) });
+		})
+	);
+}
+
+beforeEach(() => stubFetch());
+afterEach(() => {
+	cleanup();
+	vi.unstubAllGlobals();
+});
+
+describe('StammbaumSidePanel', () => {
+	it('calls onClose when dismiss button is clicked', async () => {
+		const onClose = vi.fn();
+		render(StammbaumSidePanel, { node: makeNode(), onClose, canWrite: false });
+		await expect.element(page.getByRole('button', { name: 'Schließen' })).toBeInTheDocument();
+		const btn = [...document.querySelectorAll<HTMLButtonElement>('button')].find(
+			(b) => b.getAttribute('aria-label') === 'Schließen'
+		);
+		btn!.click();
+		expect(onClose).toHaveBeenCalledOnce();
+	});
+
+	it('renders the person displayName as heading', async () => {
+		render(StammbaumSidePanel, { node: makeNode(), onClose: vi.fn(), canWrite: false });
+		await expect.element(page.getByText('Alice Müller')).toBeInTheDocument();
+	});
+
+	it('shows empty-relationships message when no direct relationships are loaded', async () => {
+		render(StammbaumSidePanel, { node: makeNode(), onClose: vi.fn(), canWrite: false });
+		await expect.element(page.getByText('Noch keine Beziehungen bekannt.')).toBeInTheDocument();
+	});
+
+	it('year inputs inside the add form have label elements (canWrite=true)', async () => {
+		render(StammbaumSidePanel, { node: makeNode(), onClose: vi.fn(), canWrite: true });
+		await expect.element(page.getByText('Noch keine Beziehungen bekannt.')).toBeInTheDocument();
+		const addBtn = [...document.querySelectorAll<HTMLButtonElement>('button')].find((b) =>
+			/Beziehung hinzufügen/i.test(b.textContent ?? '')
+		);
+		addBtn!.click();
+		await expect.element(page.getByRole('combobox')).toBeInTheDocument();
+		const yearInputs = [...document.querySelectorAll('input')].filter(
+			(i) => i.inputMode === 'numeric'
+		);
+		expect(yearInputs.length).toBeGreaterThan(0);
+		for (const input of yearInputs) {
+			expect(input.closest('label')).not.toBeNull();
+		}
+	});
+
+	it('shows loading indicator while fetching', async () => {
+		let resolveFirst: (v: unknown) => void;
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockImplementation(
+				() =>
+					new Promise((resolve) => {
+						resolveFirst = resolve;
+					})
+			)
+		);
+		render(StammbaumSidePanel, { node: makeNode(), onClose: vi.fn(), canWrite: false });
+		await expect.element(page.getByText('…')).toBeInTheDocument();
+		resolveFirst!({ ok: true, json: () => Promise.resolve([]) });
+	});
+});