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/mdast-util-gfm/index.d.ts

@@ -0,0 +1,12 @@
+import type {ToMarkdownOptions as FootnoteOptions} from 'mdast-util-gfm-footnote'
+import type {Options as TableOptions} from 'mdast-util-gfm-table'
+
+/**
+ * Configuration for `gfmToMarkdown` from `mdast-util-gfm`.
+ *
+ * Currently supports options for `mdast-util-gfm-footnote` and
+ * `mdast-util-gfm-table`.
+ */
+export interface Options extends FootnoteOptions, TableOptions {}
+
+export {gfmFromMarkdown, gfmToMarkdown} from './lib/index.js'