style: restyle podcast player to Atelier warm design system

- All CSS vars replaced with Atelier inline colors
- Warm parchment sidebar, frosted glass player bar
- Brown accent tones matching Brain/Reader/Fitness
- Route page renders component directly (no wrappers)

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

frontend-v2/src/routes/(app)/podcasts/+page.svelte

@@ -2,21 +2,4 @@
   import PodcastPlayer from '$lib/components/media/PodcastPlayer.svelte';
 </script>
 
-<div class="page">
+<PodcastPlayer />
-  <div class="app-surface">
-    <div class="page-header">
-      <div class="page-title">PODCASTS</div>
-      <div class="page-subtitle">Your podcast library</div>
-    </div>
-    <PodcastPlayer />
-  </div>
-</div>
-
-<style>
-  .page-subtitle {
-    font-size: var(--text-2xl);
-    font-weight: 300;
-    color: var(--text-1);
-    line-height: 1.2;
-  }
-</style>