Upgrade to Vite 8 and Tailwind CSS 4 (#595)

- Vite 6 → 8 (Rolldown bundler), laravel-vite-plugin 1 → 3, @vitejs/plugin-vue 5 → 6
- Tailwind CSS 3 → 4 with CSS-based config (@theme, @plugin, @utility)
- Add @tailwindcss/vite plugin, remove postcss/autoprefixer/sass
- Convert SCSS files to plain CSS (resources/sass → resources/css)
- Migrate tailwind.config.js to CSS @theme directives
- Rename deprecated utility classes (shadow-sm→shadow-xs, outline-none→outline-hidden,
  rounded-sm→rounded-xs, bg-gradient-to→bg-linear-to, ring→ring-3)
- Migrate opacity utilities to color modifiers (bg-opacity, text-opacity,
  border-opacity, ring-opacity → color/N syntax)
- Update primary color CSS vars to full rgb() values for TW4 color-mix()
- Fix border-l color specificity for sidebar navigation (TW4 default border
  color changed from gray-200 to currentColor)
- Fix invalid border color classes (border-grey-light, border-modal-bg, border--200)
- Add @reference directive for @apply in Vue component style blocks
- Convert Vue component <style lang="scss"> blocks to plain CSS

resources/scripts/components/base/BaseTabGroup.vue

@@ -3,7 +3,7 @@
     <TabGroup :default-index="defaultIndex" @change="onChange">
       <TabList
         :class="[
-          'flex border-b border-grey-light',
+          'flex border-b border-gray-200',
           'relative overflow-x-auto overflow-y-hidden',
           'lg:pb-0 lg:ml-0',
         ]"
@@ -16,7 +16,7 @@
         >
           <button
             :class="[
-              'px-8 py-2 text-sm leading-5 font-medium flex items-center relative border-b-2 mt-4 focus:outline-none whitespace-nowrap',
+              'px-8 py-2 text-sm leading-5 font-medium flex items-center relative border-b-2 mt-4 focus:outline-hidden whitespace-nowrap',
               selected
                 ? ' border-primary-400 text-black font-medium'
                 : 'border-transparent text-gray-500 hover:text-gray-700 hover:border-gray-300',