Add accent color to card title and badge icons, remove subtab separator

- Color SVG icons in card titles (.card-title, .template-name) with accent
- Color SVG icons in property badges (.stream-card-prop, .card-meta) with accent
- Revert badge icon to white on crosslink hover
- Remove border-bottom separator from subtab bar

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/css/cards.css

@@ -288,6 +288,10 @@ body.cs-drag-active .card-drag-handle {
     flex-wrap: wrap;
 }
 
+.card-title > .icon {
+    color: var(--primary-text-color);
+}
+
 .device-url-badge {
     display: inline-flex;
     align-items: center;