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/csso/lib/clean/utils.js

@@ -0,0 +1,7 @@
+export function hasNoChildren(node) {
+    return !node || !node.children || node.children.isEmpty;
+}
+
+export function isNodeChildrenList(node, list) {
+    return node !== null && node.children === list;
+}