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/document/DocumentMetadataDrawer.svelte

@@ -3,7 +3,7 @@ import { m } from '$lib/paraglide/messages.js';
 import { formatDate } from '$lib/shared/utils/date';
 import { formatDocumentStatus } from '$lib/document/documentStatusLabel';
 import { getInitials, personAvatarColor } from '$lib/person/personFormat';
-import RelationshipPill from '$lib/person/RelationshipPill.svelte';
+import RelationshipPill from '$lib/person/relationship/RelationshipPill.svelte';
 
 type Person = { id: string; firstName?: string | null; lastName: string; displayName: string };
 type Tag = { id: string; name: string };