refactor: move shared utilities to lib/shared/ sub-packages

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

frontend/src/lib/person/PersonChip.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-import { abbreviateName, getInitials, personAvatarColor } from '$lib/utils/personFormat';
+import { abbreviateName, getInitials, personAvatarColor } from '$lib/person/personFormat';
 
 type Person = { id: string; firstName?: string | null; lastName: string; displayName: string };