style: enhance PDF multi-tool UI with responsive design and scrollbar adjustments

- Added custom CSS to hide scrollbars for better aesthetics in the toolbar.
- Updated button styles for improved responsiveness and consistency across different screen sizes.
- Enhanced layout and spacing for toolbar elements and upload area for a cleaner user experience.
- Adjusted text sizes and padding for better readability and usability.

src/js/main.ts

@@ -94,7 +94,7 @@ const init = () => {
               © 2025 BentoPDF. All rights reserved.
             </p>
             <p class="text-gray-500 text-xs mt-2">
-              Version <span id="app-version-simple">1.4.0</span>
+              Version <span id="app-version-simple">1.5.0</span>
             </p>
           </div>
         `;