refactor: resolve() internal links instead of plain hrefs

Type-checks every link against the real route tree. Caught a dead one: the
book page linked tags to /tag/{id}, a route that has never existed.

frontend/src/lib/components/layout/app-sidebar.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { resolve } from '$app/paths';
 	import { Separator } from '$lib/components/ui/separator/index.js';
 
 	import ChitaiMark from '$lib/components/icons/chitai-mark.svelte';
@@ -27,7 +28,7 @@
 	// directly in the markup keeps it static.
 	const header = $derived({
 		title: 'chitai',
-		url: `/library/${libraryState.activeLibrary!.id}`
+		url: resolve('/(root)/(library)/library/[libraryId]', { libraryId: String(libraryState.activeLibrary!.id) })
 	});
 </script>
 
@@ -40,6 +41,8 @@
 		-->
 		<Sidebar.MenuButton class="mt-1 -ml-1.5">
 			{#snippet child({ props })}
+				<!-- header.url is built with resolve(); the rule cannot trace the variable. -->
+				<!-- eslint-disable-next-line svelte/no-navigation-without-resolve -->
 				<a href={header.url} {...props}>
 					<ChitaiMark class="mr-3 size-7!" />
 					<span class="font-serif text-xl tracking-tight">{header.title}</span>