Reverted to edit 92595471-e0eb-4f82-8df6-cce9b1afc166: "Add external link icons to messages

Implement CSS styles to display external link icons next to links in messages. Use a GitHub icon for GitHub links and a custom "W" icon for Wikipedia links to clearly indicate external sources. No modifications to JavaScript or TypeScript files were made.
[skip gpt_engineer]"

Author: lovable-dev[bot]

src/index.css

@@ -89,15 +89,11 @@
 
 /* GitHub icon */
 .chat-message a[href*="github.com"]::after {
-  content: "";
-  position: absolute;
-  right: 0;
-  width: 1em;
-  height: 1em;
-  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect width='20' height='20' x='2' y='2' rx='5' ry='5'/%3E%3Cpath d='M16 11.37A4 4 0 1 1 12.63 8 4 4 0 0 1 16 11.37z'/%3E%3Cline x1='17.5' y1='6.5' x2='17.51' y2='6.5'/%3E%3C/svg%3E");
-  background-size: contain;
-  background-repeat: no-repeat;
-  @apply text-muted-foreground;
+  content: "G";
+  font-family: monospace;
+  font-weight: bold;
+  font-size: 0.8em;
+  top: 0;
 }
 
 /* Wikipedia icon */