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/admin/views/modules/partials/ModuleCard.vue

@@ -3,7 +3,7 @@
     class="
       relative
       shadow-md
-      border-2 border-gray-200 border-opacity-60
+      border-2 border-gray-200/60
       rounded-lg
       cursor-pointer
       overflow-hidden
@@ -18,7 +18,7 @@
       <label
         v-if="data.purchased"
         class="
-          bg-white bg-opacity-75
+          bg-white/75
           text-xs
           px-3
           py-1
@@ -33,7 +33,7 @@
         v-if="data.installed"
         class="
           ml-2
-          bg-white bg-opacity-75
+          bg-white/75
           text-xs
           px-3
           py-1