docs: add landing page (#3448)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

docs/app/components/SkyBg.vue

@@ -0,0 +1,91 @@
+<script setup lang="ts">
+interface Star {
+  x: number
+  y: number
+  size: number
+  twinkleDelay: number
+  id: string
+}
+
+const props = withDefaults(defineProps<{
+  starCount?: number
+  color?: string
+  size?: { min: number, max: number }
+  speed?: 'slow' | 'normal' | 'fast'
+}>(), {
+  starCount: 50,
+  color: 'var(--ui-primary)',
+  size: () => ({
+    min: 1,
+    max: 3
+  }),
+  speed: 'normal'
+})
+
+// Generate random stars
+const generateStars = (count: number): Star[] => {
+  return Array.from({ length: count }, () => {
+    const x = Math.floor(Math.random() * 100)
+    const y = Math.floor(Math.random() * 100)
+    const size = Math.random() * (props.size.max - props.size.min) + props.size.min
+    const twinkleDelay = Math.random() * 5
+
+    return { x, y, size, twinkleDelay, id: Math.random().toString(36).substring(2, 9) }
+  })
+}
+
+// Generate all stars
+const stars = ref<Star[]>(generateStars(props.starCount))
+
+// Compute twinkle animation duration based on speed
+const twinkleDuration = computed(() => {
+  const speedMap: Record<string, string> = {
+    slow: '4s',
+    normal: '2s',
+    fast: '1s'
+  }
+  return speedMap[props.speed]
+})
+</script>
+
+<template>
+  <div class="absolute pointer-events-none z-[-1] inset-y-0 left-4 right-4 lg:right-[50%] overflow-hidden">
+    <ClientOnly>
+      <div
+        v-for="star in stars"
+        :key="star.id"
+        class="star absolute"
+        :style="{
+          'left': `${star.x}%`,
+          'top': `${star.y}%`,
+          'transform': 'translate(-50%, -50%)',
+          '--star-size': `${star.size}px`,
+          '--star-color': color,
+          '--twinkle-delay': `${star.twinkleDelay}s`,
+          '--twinkle-duration': twinkleDuration
+        }"
+      />
+    </ClientOnly>
+  </div>
+</template>
+
+<style scoped>
+.star {
+  width: var(--star-size);
+  height: var(--star-size);
+  background-color: var(--star-color);
+  border-radius: 50%;
+  animation: twinkle var(--twinkle-duration) ease-in-out infinite;
+  animation-delay: var(--twinkle-delay);
+  will-change: opacity;
+}
+
+@keyframes twinkle {
+  0%, 100% {
+    opacity: 0.2;
+  }
+  50% {
+    opacity: 1;
+  }
+}
+</style>