fix: symmetric card footer padding, add enlightrussia.ru to Twitch parent

- CourseCard: card body pb-0, footer py-3 — equal spacing above/below border
- StreamEmbed: add enlightrussia.ru as explicit Twitch parent domain

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

frontend/src/components/CourseCard.vue

@@ -65,7 +65,7 @@
 		</div>
 
 		<!-- Card body -->
-		<div class="flex flex-col flex-1 p-4">
+		<div class="flex flex-col flex-1 px-4 pt-4 pb-0">
 			<!-- Title (when image present): max 2 lines -->
 			<div
 				v-if="course.image"
@@ -100,7 +100,7 @@
 			</div>
 
 			<!-- Footer -->
-			<div class="flex items-center justify-between pt-2 pb-1 border-t border-outline-gray-1">
+			<div class="flex items-center justify-between py-3 border-t border-outline-gray-1">
 				<!-- Instructors -->
 				<div class="flex items-center gap-1.5">
 					<div class="flex -space-x-1.5">

frontend/src/components/StreamEmbed.vue

@@ -93,11 +93,11 @@ const embedUrl = computed(() => {
 
 	if (props.platform === 'twitch') {
 		// Twitch requires parent= for every domain the embed runs on.
-		// Collect unique hostnames: current + localhost fallback
-		const hosts = new Set<string>()
-		hosts.add(window.location.hostname || 'localhost')
-		// Always include localhost so dev server works too
-		hosts.add('localhost')
+		const hosts = new Set<string>([
+			'enlightrussia.ru',
+			'localhost',
+			window.location.hostname,
+		].filter(Boolean))
 		const parentParams = [...hosts].map(h => `parent=${h}`).join('&')
 		return `https://player.twitch.tv/?channel=${props.channel}&${parentParams}&autoplay=false`
 	}