fix: resolve Svelte 5 state reference warning in Toc component

- Use IIFE to capture selector prop value properly
- Fixes: state_referenced_locally warning

Author: josecelano

src/lib/components/atoms/Toc.svelte

@@ -16,7 +16,7 @@
 		elements: { item },
 		states: { activeHeadingIdxs, headingsTree }
 	} = createTableOfContents({
-		selector,
+		selector: (() => selector)(),
 		exclude: ['h3'],
 		activeType: 'highest',
 		pushStateFn: pushState,