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/css/components/animation.css

@@ -0,0 +1,29 @@
+.shake {
+  animation: shake 0.82s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
+  transform: translate3d(0, 0, 0);
+  backface-visibility: hidden;
+  perspective: 1000px;
+}
+
+@keyframes shake {
+  10%,
+  90% {
+    transform: translate3d(-1px, 0, 0);
+  }
+
+  20%,
+  80% {
+    transform: translate3d(2px, 0, 0);
+  }
+
+  30%,
+  50%,
+  70% {
+    transform: translate3d(-4px, 0, 0);
+  }
+
+  40%,
+  60% {
+    transform: translate3d(4px, 0, 0);
+  }
+}