feat: Add packages/site — landing vitrine (Vue 3 + Tailwind 4)

- Scaffold packages/site with 11 Vue components: hero (animated terminal), features, showcase, work groups, how-it-works, security, FAQ accordion, footer
- i18n EN/FR via vue-i18n with 82+ keys, autodetect navigator.language, toggle without reload
- Animated timeline (terminal, dialog, toast) ported from design, scroll-reveal, copy buttons (2 instances)
- Self-hosted JetBrains Mono fonts (@fontsource), optimized assets (mark 28KB, og-cover 1200×630)
- SEO: canonical, og:image, theme-color, robots.txt, sitemap.xml for git-arboretum.com
- Monorepo integration (decoupled from npm release): build:site / dev:site / preview:site scripts
- CI: add build:site step to ci.yml for early detection; create .gitea/workflows/prod.yml for FTPS deploy (lftp mirror) to git-arboretum.com
- Validated builds ✓ and UI rendering (EN/FR headless test) ✓

packages/site/src/components/AppFooter.vue

@@ -0,0 +1,47 @@
+<script setup lang="ts">
+import { useI18n } from 'vue-i18n';
+import IconGitea from './icons/IconGitea.vue';
+
+const { t } = useI18n();
+const REPO = 'https://git.lidge.fr/johanleroy/git-arboretum';
+const LICENSE = 'https://git.lidge.fr/johanleroy/git-arboretum/src/branch/main/LICENSE';
+const COFFEE = 'https://buymeacoffee.com/johanleroy';
+</script>
+
+<template>
+  <footer class="relative z-[1] border-t border-[#1c1c1f]">
+    <div class="mx-auto flex max-w-[1200px] flex-wrap items-center justify-between gap-5 px-6 py-[34px]">
+      <div class="flex items-center gap-[11px]">
+        <img
+          src="/assets/arboretum-mark.png"
+          alt=""
+          width="22"
+          height="22"
+          class="h-[22px] w-[22px] object-contain"
+          style="filter: grayscale(1) brightness(1.5); opacity: 0.4"
+        />
+        <span class="font-mono text-sm text-zinc-300">git-arboretum.com</span>
+        <span class="ml-1 text-[13px] text-zinc-600">— {{ t('footTag') }}</span>
+      </div>
+      <div class="flex items-center gap-[22px] text-sm">
+        <a :href="REPO" target="_blank" rel="noopener" class="inline-flex items-center gap-1.5 text-zinc-400 no-underline transition-colors hover:text-emerald-400">
+          <IconGitea :size="15" />
+          Gitea
+        </a>
+        <a :href="LICENSE" target="_blank" rel="noopener" class="text-zinc-400 no-underline transition-colors hover:text-emerald-400">
+          {{ t('license') }}
+        </a>
+        <a
+          :href="COFFEE"
+          target="_blank"
+          rel="noopener"
+          class="inline-flex items-center gap-1.5 text-zinc-400 no-underline transition-colors hover:text-amber-400 focus-visible:rounded-md focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-amber-400/70"
+        >
+          <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.7" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M10 2v2" /><path d="M14 2v2" /><path d="M5 8h13a1 1 0 0 1 1 1v2a4 4 0 0 1-4 4H8a4 4 0 0 1-4-4V9a1 1 0 0 1 1-1Z" /><path d="M6 15a4 4 0 0 0 4 4h2a4 4 0 0 0 4-4" /><path d="M19 9h1.5a2.5 2.5 0 0 1 0 5H18" /></svg>
+          {{ t('coffee') }}
+        </a>
+        <span class="font-mono text-[12.5px] text-zinc-600">npx @johanleroy/git-arboretum</span>
+      </div>
+    </div>
+  </footer>
+</template>