Added responsive horizontal padding to VersionSelector search bar

- **Search bar padding added**: px-4 sm:px-6 lg:px-8 to match App main container
- **Consistent centering**: Ensures search bar aligns identically with other pages
- **Responsive padding**: Same responsive behavior across breakpoints
- **Fixed centering shift**: Eliminates visual difference between pages

Version selector search bar centering now perfectly matches all other pages!

frontend/src/components/VersionSelector.tsx

@@ -10,7 +10,7 @@ const VersionSelector: React.FC<VersionSelectorProps> = ({ onVersionSelect, onSe
   return (
     <div>
       {/* Search Bar */}
-      <div className="flex justify-center mb-4">
+      <div className="flex justify-center mb-4 px-4 sm:px-6 lg:px-8">
         <div className="w-full max-w-md relative">
           <input
             type="text"