chore: clear the mechanical lint and type findings

Dead imports and locals removed, each blocks keyed, `any` narrowed to unknown.
Two context setters kept their calls and lost only the unused binding; the
settings redirect no longer awaits a parent whose data it discards. A leading
underscore now marks a binding that only holds a position.

frontend/src/lib/components/forms/book-delete.svelte

@@ -3,8 +3,6 @@
 	import { Checkbox } from '$lib/components/ui/checkbox/index.js';
 	import { Button } from '$lib/components/ui/button/index.js';
 	import * as Dialog from '$lib/components/ui/dialog/index.js';
-	import { getBookSelectionState } from '$lib/state/bookSelection.svelte';
-	import { getBookOperationsState } from '$lib/state/bookOperations.svelte';
 
 	let {
 		open = $bindable(),
@@ -16,9 +14,6 @@
 		deleteFn: (deleteFiles: boolean) => void | Promise<void>;
 	} = $props();
 
-	const selectedState = getBookSelectionState();
-	const bookOps = getBookOperationsState();
-
 	let deleteFiles = $state(false);
 </script>