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/remark-gfm/index.d.ts

@@ -0,0 +1,13 @@
+import type {Options as MicromarkOptions} from 'micromark-extension-gfm'
+import type {Options as MdastOptions} from 'mdast-util-gfm'
+
+export {default} from './lib/index.js'
+
+/**
+ * Configuration for `remark-gfm`.
+ *
+ * Currently supports `singleTilde` as a parse option and
+ * `firstLineBlank`, `stringLength`, `tableCellPadding`, and `tablePipeAlign`
+ * as serialization options.
+ */
+export interface Options extends MicromarkOptions, MdastOptions {}