Redesign frontend UI with Observatory theme

New teal-accent color system, DM Sans + JetBrains Mono typography,
glow effects, animated gradient login page, animated dashboard counters
with gradient-border stat cards, event timeline, sidebar with active
glow indicators, and polished components (modals, cards, snackbar).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/PageHeader.svelte

@@ -6,14 +6,16 @@
 	}>();
 </script>
 
-<div class="flex items-center justify-between mb-6">
-	<div>
+<div class="flex items-center justify-between mb-8">
+	<div class="animate-fade-slide-in">
 		<h2 class="text-2xl font-semibold tracking-tight">{title}</h2>
 		{#if description}
-			<p class="text-sm text-[var(--color-muted-foreground)] mt-1">{description}</p>
+			<p class="text-sm mt-1.5" style="color: var(--color-muted-foreground);">{description}</p>
 		{/if}
 	</div>
 	{#if children}
-		{@render children()}
+		<div class="animate-fade-slide-in" style="animation-delay: 60ms;">
+			{@render children()}
+		</div>
 	{/if}
 </div>