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/vfile/lib/minproc.browser.js

@@ -0,0 +1,8 @@
+// Somewhat based on:
+// <https://github.com/defunctzombie/node-process/blob/master/browser.js>.
+// But I don’t think one tiny line of code can be copyrighted. 😅
+export const minproc = {cwd}
+
+function cwd() {
+  return '/'
+}