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/BaseDropdown.vue

@@ -11,7 +11,7 @@
       />
     </BaseContentPlaceholders>
     <Menu v-else>
-      <MenuButton ref="trigger" class="focus:outline-none" @click="onClick">
+      <MenuButton ref="trigger" class="focus:outline-hidden" @click="onClick">
         <slot name="activator" />
       </MenuButton>
 
@@ -69,7 +69,7 @@ const props = defineProps({
 })
 
 const containerClasses = computed(() => {
-  const baseClass = `origin-top-right rounded-md shadow-lg bg-white ring-1 ring-black ring-opacity-5 divide-y divide-gray-100 focus:outline-none`
+  const baseClass = `origin-top-right rounded-md shadow-lg bg-white ring-1 ring-black/5 divide-y divide-gray-100 focus:outline-hidden`
   return `${baseClass} ${props.containerClass}`
 })