feat(ui): add PersonChip component — avatar initials, abbreviated prop

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

frontend/src/lib/components/PersonChip.svelte

@@ -0,0 +1,33 @@
+<script lang="ts">
+import { abbreviateName, personAvatarColor } from '$lib/utils/personFormat';
+
+type Person = { id: string; firstName: string; lastName: string };
+
+type Props = {
+	person: Person;
+	abbreviated: boolean;
+};
+
+let { person, abbreviated }: Props = $props();
+
+const displayName = $derived(
+	abbreviated ? abbreviateName(person) : `${person.firstName} ${person.lastName}`
+);
+const avatarColor = $derived(personAvatarColor(person.id));
+const initials = $derived(
+	`${person.firstName.charAt(0)}${person.lastName.charAt(0)}`.toUpperCase()
+);
+</script>
+
+<span
+	class="inline-flex shrink-0 items-center gap-1.5 rounded-full border border-line bg-muted px-2 py-0.5"
+>
+	<span
+		class="flex h-4 w-4 shrink-0 items-center justify-center rounded-full text-[8px] font-bold text-white"
+		style="background-color: {avatarColor}"
+		aria-hidden="true"
+	>
+		{initials}
+	</span>
+	<span class="text-[9px] font-semibold text-ink">{displayName}</span>
+</span>