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/pages/projects/project-view-1/roadmap/project-view-roadmap.tsx

@@ -21,7 +21,7 @@ const ProjectViewRoadmap = () => {
 
       <Flex>
         {/* table */}
-        <div className="after:content relative h-fit w-full max-w-[500px] after:absolute after:-right-3 after:top-0 after:z-10 after:min-h-full after:w-3 after:bg-gradient-to-r after:from-[rgba(0,0,0,0.12)] after:to-transparent">
+        <div className="after:content relative h-fit w-full max-w-[500px] after:absolute after:-right-3 after:top-0 after:z-10 after:min-h-full after:w-3 after:bg-linear-to-r after:from-[rgba(0,0,0,0.12)] after:to-transparent">
           <RoadmapTable />
         </div>