feat(site): standalone landing page for Vercel

Static single-file page in site/ matching the app theme (dark #0c0d0f,
lime #b4e34a, self-hosted Inter + JetBrains Mono). Real product
screenshots, install one-liner with copy button, template marquee,
tabbed gallery. No build step; deployed via vercel deploy --prod.

Live: https://containr-lyart.vercel.app

Authored By: TDvorak <[email protected]>

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

site/containr.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="64" y2="64" gradientUnits="userSpaceOnUse">
+      <stop offset="0" stop-color="#cdf06f"/>
+      <stop offset="1" stop-color="#7fb524"/>
+    </linearGradient>
+  </defs>
+  <rect width="64" height="64" rx="15" fill="url(#bg)"/>
+  <g fill="none" stroke="#131507" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round">
+    <rect x="15" y="18" width="34" height="26" rx="4"/>
+    <path d="M23 18v26M31 18v26M39 18v26"/>
+    <path d="M20 51h24"/>
+  </g>
+</svg>