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/styles/main.css

@@ -644,6 +644,38 @@ input:focus-visible {
     inset 0 1px 0 rgba(255, 255, 255, 0.5);
 }
 
+/* Empty state icon — app icon in glassmorphic square, white, path-glass border */
+.empty-state-icon {
+  position: relative;
+}
+
+/* Frosted glass center behind the icon */
+.empty-state-icon::before {
+  content: '';
+  position: absolute;
+  inset: 15%;
+  border-radius: 50%;
+  background: rgba(255, 255, 255, 0.06);
+  backdrop-filter: blur(12px);
+  -webkit-backdrop-filter: blur(12px);
+  pointer-events: none;
+}
+
+.empty-state-icon img {
+  position: relative;
+  z-index: 1;
+  filter: brightness(0) invert(1);
+}
+
+.light .empty-state-icon::before {
+  background: rgba(0, 0, 0, 0.04);
+}
+
+.light .empty-state-icon img {
+  filter: brightness(0) saturate(100%);
+  opacity: 0.75;
+}
+
 .animate-fade-up {
   animation: fadeUpIn 900ms cubic-bezier(0.22, 1, 0.36, 1) 120ms both;
 }