chore(dependencies): update Tailwind CSS and related packages for improved styling

- Added @tailwindcss/postcss as a new dependency.
- Updated tailwindcss to version 4.1.11 for enhanced features and performance.
- Upgraded prettier-plugin-tailwindcss to version 0.6.13 for better formatting support.
- Adjusted postcss.config.js to use the new Tailwind CSS plugin structure.
- Removed the obsolete tailwind.config.js file as it is no longer needed.

worklenz-frontend/src/components/Tooltip.tsx

@@ -25,7 +25,7 @@ const Tooltip: React.FC<TooltipProps> = ({
   return (
     <div className={`relative group ${className}`}>
       {children}
-      <div className={`absolute ${placementClasses[placement]} px-2 py-1 text-xs text-white ${isDarkMode ? 'bg-gray-700' : 'bg-gray-900'} rounded shadow-lg opacity-0 group-hover:opacity-100 transition-opacity duration-200 z-50 pointer-events-none min-w-max`}>
+      <div className={`absolute ${placementClasses[placement]} px-2 py-1 text-xs text-white ${isDarkMode ? 'bg-gray-700' : 'bg-gray-900'} rounded-sm shadow-lg opacity-0 group-hover:opacity-100 transition-opacity duration-200 z-50 pointer-events-none min-w-max`}>
         {title}
       </div>
     </div>