feat(landing): rebuild as Next.js app with live product mocks

Replaces the static HTML page with a Next.js 15 + Tailwind v4 + Motion
app. The hero renders the dashboard itself - live tiles, ticking clock,
wandering metrics, pulsing status dots - instead of screenshots. Adds a
playable four-renderer switcher (bento/cards/index/console) with layout
animations, live monitor/domain/system mocks, and a cycling alert feed.

Vercel project dash is now git-connected with root dir landing/; pushes
deploy automatically. Canonical alias: dash-homelab.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>

landing/app/icon.svg

@@ -0,0 +1,9 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
+  <rect width="512" height="512" rx="104" fill="#0a0a0a"/>
+  <g fill="#3b82f6">
+    <rect x="120" y="120" width="124" height="124" rx="28"/>
+    <rect x="268" y="120" width="124" height="124" rx="28" fill="#6b9ef8"/>
+    <rect x="120" y="268" width="124" height="124" rx="28" fill="#1d4fd7"/>
+    <rect x="268" y="268" width="124" height="124" rx="28"/>
+  </g>
+</svg>