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-strikethrough/index.d.ts

@@ -0,0 +1,19 @@
+export {
+  gfmStrikethroughFromMarkdown,
+  gfmStrikethroughToMarkdown
+} from './lib/index.js'
+
+// Add custom data tracked to turn a syntax tree into markdown.
+declare module 'mdast-util-to-markdown' {
+  interface ConstructNameMap {
+    /**
+     * Whole strikethrough.
+     *
+     * ```markdown
+     * > | ~~a~~
+     *     ^^^^^
+     * ```
+     */
+    strikethrough: 'strikethrough'
+  }
+}