fix: Fix product page syntax errors

1. Remove duplicate/broken code in product tables section
2. Fix PostCSS config for Tailwind 4
3. Add @tailwindcss/postcss dependency
4. Remove --production flag from Dockerfile (sharp required)

All fixes enable successful Docker build with favicon working.

node_modules/retext-stringify/index.d.ts

@@ -0,0 +1,14 @@
+import type {Root} from 'nlcst'
+import type {Plugin} from 'unified'
+
+/**
+ * Add support for serializing natural language.
+ *
+ * @this
+ *   Unified processor.
+ * @returns
+ *   Nothing.
+ */
+declare const retextStringify: Plugin<[], Root, string>
+
+export default retextStringify