feat: add Electron desktop app

src/index.css

@@ -129,6 +129,8 @@
   body {
     @apply bg-background text-foreground;
     font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
+    -webkit-font-smoothing: antialiased;
+    -moz-osx-font-smoothing: grayscale;
     margin: 0;
     padding: 0;
   }
@@ -555,6 +557,30 @@
 
 /* Mobile optimizations and components */
 @layer components {
+  .chat-messages-pane {
+    contain: layout style paint;
+  }
+
+  .chat-composer-shell {
+    contain: layout style paint;
+  }
+
+  .chat-message {
+    contain: layout style paint;
+    content-visibility: auto;
+    contain-intrinsic-size: auto 180px;
+  }
+
+  .chat-message.assistant {
+    contain-intrinsic-size: auto 240px;
+  }
+
+  .chat-message.user,
+  .chat-message.tool,
+  .chat-message.error {
+    contain-intrinsic-size: auto 96px;
+  }
+
   /* Mobile touch optimization and safe areas */
   @media (max-width: 768px) {
     * {