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/BaseSelectInput.vue

@@ -30,9 +30,9 @@
           bg-white
           border border-gray-200
           rounded-md
-          shadow-sm
+          shadow-xs
           cursor-default
-          focus:outline-none
+          focus:outline-hidden
           focus:ring-1
           focus:ring-primary-500
           focus:border-primary-500
@@ -86,8 +86,8 @@
             rounded-md
             shadow-lg
             max-h-60
-            ring-1 ring-black ring-opacity-5
-            focus:outline-none
+            ring-1 ring-black/5
+            focus:outline-hidden
             sm:text-sm
           "
         >