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/retext-stringify/lib/index.d.ts

@@ -0,0 +1,8 @@
+/**
+ * Add support for serializing natural language.
+ *
+ * @returns {undefined}
+ *   Nothing.
+ */
+export default function retextStringify(): undefined;
+export type Root = import('nlcst').Root;

node_modules/retext-stringify/lib/index.js

@@ -0,0 +1,27 @@
+/**
+ * @typedef {import('nlcst').Root} Root
+ */
+
+import {toString} from 'nlcst-to-string'
+
+/**
+ * Add support for serializing natural language.
+ *
+ * @returns {undefined}
+ *   Nothing.
+ */
+export default function retextStringify() {
+  // eslint-disable-next-line unicorn/no-this-assignment
+  const self =
+    /** @type {import('unified').Processor<undefined, undefined, undefined, Root, string>} */ (
+      // @ts-expect-error -- TS in JSDoc doesn’t understand `this`.
+      this
+    )
+
+  self.compiler = compiler
+}
+
+/** @type {import('unified').Compiler<Root, string>} */
+function compiler(tree) {
+  return toString(tree)
+}