Update AI copilot icon and tooltip for better UX

- Replace star design with clean plus sign icons (larger + smaller)
- Update tooltip from 'Switch to AI Copilot' to 'Switch to AI chat'
- Creates visual hierarchy with size difference between plus signs
- More direct and user-friendly language for the AI functionality
- Cleaner, geometric design that's more subtle and professional

This provides clearer communication about what the button does while maintaining a clean, modern aesthetic.

Author: mich-elle-luna

layouts/partials/search-modal.html

@@ -23,10 +23,12 @@
           <path d="M10 10l5.09-5.09L10 10l5.09 5.09L10 10zm0 0L4.91 4.91 10 10l-5.09 5.09L10 10z" stroke="currentColor" fill="none" fill-rule="evenodd" stroke-linecap="round" stroke-linejoin="round" />
         </svg>
       </button>
-      <button id="ai-copilot-toggle" type="button" style="height: calc(3rem - 2px);" class="px-3 border border-redis-pen-800 rounded-md bg-white hover:bg-redis-yellow-100 transition-colors flex items-center gap-2" title="Switch to AI Copilot">
-        <svg width="16" height="16" viewBox="0 0 20 20" fill="currentColor">
-          <path d="M6 2.5L7.5 6.5L11.5 7L8.5 9.5L9.5 13.5L6 11.5L2.5 13.5L3.5 9.5L0.5 7L4.5 6.5L6 2.5Z"></path>
-          <path d="M14 6.5L15.5 10.5L19.5 11L16.5 13.5L17.5 17.5L14 15.5L10.5 17.5L11.5 13.5L8.5 11L12.5 10.5L14 6.5Z"></path>
+      <button id="ai-copilot-toggle" type="button" style="height: calc(3rem - 2px);" class="px-3 border border-redis-pen-800 rounded-md bg-white hover:bg-redis-yellow-100 transition-colors flex items-center gap-2" title="Switch to AI chat">
+        <svg width="16" height="16" viewBox="0 0 16 16" fill="currentColor">
+          <!-- Larger plus in top left -->
+          <path d="M3 2h2v2h2v2h-2v2h-2v-2h-2v-2h2v-2z"/>
+          <!-- Smaller plus in bottom right -->
+          <path d="M11 9h1v1h1v1h-1v1h-1v-1h-1v-1h1v-1z"/>
         </svg>
         <span class="text-sm">AI</span>
       </button>