fix(observability): router conflict, logout button, missing i18n

- Fix chi duplicate Route() panic by consolidating read/write routes
  into single Route blocks with nested admin Group
- Add logout button to sidebar with token cleanup
- Add missing settingsAuth.password i18n key

web/src/lib/components/icons/IconLogout.svelte

@@ -0,0 +1,9 @@
+<script lang="ts">
+	interface Props { size?: number; class?: string; }
+	const { size = 24, class: className = '' }: Props = $props();
+</script>
+<svg width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class={className}>
+	<path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4" />
+	<polyline points="16 17 21 12 16 7" />
+	<line x1="21" y1="12" x2="9" y2="12" />
+</svg>