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/StammbaumCard.svelte.spec.ts

@@ -0,0 +1,54 @@
+import { describe, it, expect, afterEach, vi } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import StammbaumCard from './StammbaumCard.svelte';
+
+vi.mock('$app/forms', () => ({ enhance: () => () => {} }));
+vi.mock('$lib/person/relationship/RelationshipChip.svelte', () => ({ default: () => null }));
+vi.mock('$lib/person/relationship/AddRelationshipForm.svelte', () => ({ default: () => null }));
+
+afterEach(cleanup);
+
+const baseProps = {
+	personId: 'person-1',
+	familyMember: false,
+	relationships: [],
+	inferredRelationships: [],
+	canWrite: false
+};
+
+describe('StammbaumCard', () => {
+	it('renders the section heading', async () => {
+		render(StammbaumCard, baseProps);
+		await expect.element(page.getByText('Stammbaum & Beziehungen')).toBeInTheDocument();
+	});
+
+	it('shows empty-relationships message when relationships list is empty', async () => {
+		render(StammbaumCard, baseProps);
+		await expect.element(page.getByText('Noch keine Beziehungen bekannt.')).toBeInTheDocument();
+	});
+
+	it('renders the family-member toggle when canWrite is true', async () => {
+		render(StammbaumCard, { ...baseProps, canWrite: true });
+		await expect.element(page.getByText('Als Familienmitglied')).toBeInTheDocument();
+	});
+
+	it('displays relationshipError text when provided', async () => {
+		render(StammbaumCard, { ...baseProps, relationshipError: 'Test Fehler' });
+		await expect.element(page.getByText('Test Fehler')).toBeInTheDocument();
+	});
+
+	it('toggle aria-label says "Zum Stammbaum hinzufügen" when not yet a family member', async () => {
+		render(StammbaumCard, { ...baseProps, canWrite: true, familyMember: false });
+		await expect
+			.element(page.getByRole('switch', { name: 'Zum Stammbaum hinzufügen' }))
+			.toBeInTheDocument();
+	});
+
+	it('toggle aria-label says "Aus Stammbaum entfernen" when already a family member', async () => {
+		render(StammbaumCard, { ...baseProps, canWrite: true, familyMember: true });
+		await expect
+			.element(page.getByRole('switch', { name: 'Aus Stammbaum entfernen' }))
+			.toBeInTheDocument();
+	});
+});