feat: card highlight system for cross-entity navigation

When clicking a CrossLink, the target entity ID is passed as
?highlight=<id> in the URL. The destination page:
1. Shows a semi-transparent dim overlay (z-index: 10)
2. Finds the card with data-entity-id matching the ID
3. Scrolls to it smoothly (block: center)
4. Applies a pulsing primary-color box-shadow animation (z-index: 11)
5. Cleans up overlay + animation after 2 seconds

If the card isn't in DOM yet (data still loading), a MutationObserver
waits up to 5 seconds for it to appear.

Changes:
- New highlight.ts utility with highlightFromUrl(), MutationObserver,
  dim overlay management
- Card component accepts entityId prop → data-entity-id attribute
- CrossLink accepts entityId prop → appends ?highlight=<id> to href
- All 9 entity pages: Card elements have entityId, highlightFromUrl()
  called after data loads
- CSS: cardHighlight keyframe animation + nav-dim-overlay styles

frontend/src/routes/command-configs/+page.svelte

@@ -13,6 +13,7 @@
 	import IconButton from '$lib/components/IconButton.svelte';
 	import CrossLink from '$lib/components/CrossLink.svelte';
 	import { snackSuccess, snackError } from '$lib/stores/snackbar.svelte';
+	import { highlightFromUrl } from '$lib/highlight';
 
 	function templateName(id: number | null): string {
 		if (!id) return '';
@@ -67,7 +68,7 @@
 				commandTemplateConfigsCache.fetch(),
 			]);
 		} catch (err: any) { error = err.message || t('common.loadError'); snackError(error); }
-		finally { loaded = true; }
+		finally { loaded = true; highlightFromUrl(); }
 	}
 
 	function openNew() {
@@ -238,7 +239,7 @@
 {:else}
 	<div class="space-y-3 stagger-children">
 		{#each configs as cfg}
-			<Card hover>
+			<Card hover entityId={cfg.id}>
 				<div class="flex items-center justify-between">
 					<div>
 						<div class="flex items-center gap-2">
@@ -256,7 +257,7 @@
 								&middot; {t('commandConfig.defaultCount')}: {cfg.default_count}
 							</span>
 							{#if cfg.command_template_config_id}
-								<CrossLink href="/command-template-configs" icon="mdiCodeBracesBox" label={templateName(cfg.command_template_config_id)} />
+								<CrossLink href="/command-template-configs" icon="mdiCodeBracesBox" label={templateName(cfg.command_template_config_id)} entityId={cfg.command_template_config_id} />
 							{/if}
 						</div>
 					</div>