chore: Update package.json to manage @tailwindcss/postcss dependency

- Added @tailwindcss/postcss to dependencies for improved styling capabilities.
- Removed it from devDependencies to streamline package management.

package.json

@@ -21,6 +21,7 @@
     "db:seed": "tsx prisma/seed.ts"
   },
   "dependencies": {
+    "@tailwindcss/postcss": "^4",
     "@prisma/adapter-pg": "^7.2.0",
     "@prisma/client": "^7.2.0",
     "bcryptjs": "^3.0.3",
@@ -33,7 +34,6 @@
     "react-dom": "19.2.3"
   },
   "devDependencies": {
-    "@tailwindcss/postcss": "^4",
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.1",
     "@testing-library/user-event": "^14.6.1",