feat(chat): integrate podcast support into chat components

- Updated ChatMessage and ChatWindow components to handle podcast content alongside films and songs.
- Enhanced useContentPanel to extract and manage podcasts, allowing for richer media interactions.
- Added PodcastCard and PodcastGrid components for displaying podcast information.
- Improved UI elements to accommodate podcast selection and detail viewing.
- Updated styles for empty state icons and added new CSS for podcast-related elements.

Made-with: Cursor

packages/app/src/components/content/SongGrid.vue

@@ -4,13 +4,16 @@
       ? 'border-bottom: 1px solid rgba(255, 255, 255, 0.08)'
       : 'border-bottom: 1px solid rgba(0, 0, 0, 0.06)'"
     >
-      <div class="flex items-center justify-between">
+      <div class="flex items-center justify-between gap-2">
         <h3 class="text-sm font-bold" :class="isDark ? 'text-white/90' : 'text-gray-900'">
           {{ title }}
         </h3>
-        <span class="text-[10px] font-mono" :class="isDark ? 'text-white/30' : 'text-gray-400'">
-          {{ filteredSongs.length }} songs
-        </span>
+        <div class="flex items-center gap-2 shrink-0">
+          <span class="text-[10px] font-mono" :class="isDark ? 'text-white/30' : 'text-gray-400'">
+            {{ filteredSongs.length }} songs
+          </span>
+          <slot name="header-actions" />
+        </div>
       </div>
 
       <input