fix: prevent stagger animation replay after card highlight ends

Use inline style.animation instead of CSS class to avoid triggering
stagger-children fadeSlideIn re-animation when highlight is removed.
Restores original inline styles on cleanup.

frontend/src/app.css

@@ -190,12 +190,6 @@ a:focus-visible {
 	25%, 75% { box-shadow: 0 0 0 3px var(--color-primary), 0 0 20px color-mix(in srgb, var(--color-primary) 30%, transparent); }
 }
 
-.card-highlight {
-	animation: cardHighlight 2s ease-in-out;
-	position: relative;
-	z-index: 11;
-}
-
 .nav-dim-overlay {
 	position: fixed;
 	inset: 0;