Add the cnxvinyl.lol test site with a Gitea deploy workflow

site/ builds the internal test site: public/ served as is (landing page,
robots.txt, static sites) plus demo pages copied out of docs/ (the plant
operation page at /demos/plant-operation/). build.sh fails on dead
internal links and stamps version.txt.

.gitea/workflows/deploy-site.yml rsyncs site/dist to the buildfor.life
web server with the blog's two-directory rename swap, checks version.txt
on the server, purges Cloudflare when a token is set, and checks the
public URL. Secret names match the blog's workflow.

site/Caddyfile is the virtual host to append on s1 (noindex everywhere,
Cloudflare-only like the blog apex, www redirect). site/README.md has the
one-time setup: DNS, Caddy, web root, secrets, runner.

site/public/index.html

@@ -0,0 +1,68 @@
+<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<meta name="robots" content="noindex, nofollow">
+<title>CNX Vinyl · internal test site</title>
+<style>
+  :root {
+    --bg: #0a0f1a; --panel: #0f1626; --stroke: #2a3a56;
+    --fg: #d6deeb; --mute: #8a97b0; --accent: #3ddc84;
+  }
+  * { box-sizing: border-box; }
+  body {
+    margin: 0; background: var(--bg); color: var(--fg);
+    font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
+  }
+  main { max-width: 760px; margin: 0 auto; padding: 48px 20px; }
+  h1 { margin: 0; font-size: 28px; letter-spacing: 0.02em; }
+  .tag {
+    display: inline-block; margin-top: 6px; padding: 2px 8px;
+    border: 1px solid var(--stroke); border-radius: 4px;
+    color: var(--mute); font-size: 13px;
+  }
+  p.lead { color: var(--mute); margin: 18px 0 32px; }
+  h2 {
+    font-size: 13px; text-transform: uppercase; letter-spacing: 0.08em;
+    color: var(--mute); margin: 32px 0 12px;
+  }
+  ul { list-style: none; margin: 0; padding: 0; }
+  li a {
+    display: block; padding: 14px 16px; margin-bottom: 10px;
+    background: var(--panel); border: 1px solid var(--stroke); border-radius: 6px;
+    color: var(--fg); text-decoration: none;
+  }
+  li a:hover, li a:focus-visible { border-color: var(--accent); }
+  li strong { display: block; color: var(--accent); font-weight: 600; }
+  li span { color: var(--mute); font-size: 14px; }
+  footer { margin-top: 40px; color: var(--mute); font-size: 13px; }
+</style>
+</head>
+<body>
+<main>
+  <h1>CNX Vinyl</h1>
+  <span class="tag">internal test site</span>
+  <p class="lead">
+    Demos and static pages from the CNX Vinyl planning repository, a vinyl
+    pressing plant planned near Chiang Mai. Shared by link only and not
+    indexed. Figures in the demos are planning estimates.
+  </p>
+
+  <h2>Demos</h2>
+  <ul>
+    <li>
+      <a href="demos/plant-operation/">
+        <strong>Plant overview (simulated SCADA)</strong>
+        <span>The whole plant animated, from PVC intake and the material lab
+        through extruder, press, trim, optical inspection, finishing,
+        packaging and fulfillment, with the metal path, utilities and energy
+        alongside. Every station is clickable.</span>
+      </a>
+    </li>
+  </ul>
+
+  <footer>Built from <code>site/</code> in the cnx_vinyl repository.</footer>
+</main>
+</body>
+</html>

site/public/robots.txt

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+User-agent: *
+Disallow: /