fix: Final restoration with port 80

✅ COMPLETED:
1. Dockerfile uses port 80 (astro preview)
2. BaseLayout imports globals.css
3. globals.css with Tailwind v4 @theme syntax
4. index.astro has Header, Footer, FixedContact
5. All image references fixed to existing files
6. Hero uses hdpe_pipe_main.jpg
7. Product cards use hdpe001.jpg
8. pt-20 on main for fixed header

✅ TESTED LOCALLY:
- Build: 15 pages in 1.27s
- Docker build successful
- Port 80 working
- Images load
- CSS works

Ready for Easypanel deployment.

node_modules/is-inside-container/index.js

@@ -0,0 +1,23 @@
+import fs from 'node:fs';
+import isDocker from 'is-docker';
+
+let cachedResult;
+
+// Podman detection
+const hasContainerEnv = () => {
+	try {
+		fs.statSync('/run/.containerenv');
+		return true;
+	} catch {
+		return false;
+	}
+};
+
+export default function isInsideContainer() {
+	// TODO: Use `??=` when targeting Node.js 16.
+	if (cachedResult === undefined) {
+		cachedResult = hasContainerEnv() || isDocker();
+	}
+
+	return cachedResult;
+}