Add PersonaSelector component for quick persona switching

src/lib/components/PersonaSelector.svelte

@@ -0,0 +1,22 @@
+<script lang="ts">
+	import { goto } from "$app/navigation";
+	import { base } from "$app/paths";
+	import { useSettingsStore } from "$lib/stores/settings";
+	import CarbonUser from "~icons/carbon/user";
+
+	const settings = useSettingsStore();
+
+	let activePersona = $derived(
+		$settings.personas.find((p) => p.id === $settings.activePersona) ?? $settings.personas[0]
+	);
+</script>
+
+<button
+	class="flex items-center gap-1.5 rounded-lg border border-gray-300 bg-gray-100 px-3 py-1.5 text-sm text-gray-700 shadow-sm hover:bg-gray-200 dark:border-gray-600 dark:bg-gray-800 dark:text-gray-300 dark:hover:bg-gray-700"
+	onclick={() => goto(`${base}/settings/personas`)}
+	title="Manage personas"
+>
+	<CarbonUser class="text-xs" />
+	<span class="max-w-[150px] truncate">{activePersona?.name ?? "Default"}</span>
+</button>
+