feat(isac): add specialization data management

src/lib/components/ItemIcon.svelte

@@ -1,4 +1,6 @@
 <script lang="ts">
+	import { MISSING_ITEM_ICON_URL } from '$lib/item-icons';
+
 	let {
 		src = '',
 		alt = '',
@@ -8,6 +10,8 @@
 		alt?: string;
 		className?: string;
 	} = $props();
+
+	const resolvedAlt = $derived(src || !alt ? alt : `${alt} — icon awaiting contribution`);
 </script>
 
-<img src={src || '/missing-item-icon.svg'} {alt} class:missing-item-icon={!src} class={className}/>
+<img src={src || MISSING_ITEM_ICON_URL} alt={resolvedAlt} class:missing-item-icon={!src} class={className}/>