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-to-markdown/lib/handle/thematic-break.js

@@ -0,0 +1,21 @@
+/**
+ * @import {State} from 'mdast-util-to-markdown'
+ * @import {Parents, ThematicBreak} from 'mdast'
+ */
+
+import {checkRuleRepetition} from '../util/check-rule-repetition.js'
+import {checkRule} from '../util/check-rule.js'
+
+/**
+ * @param {ThematicBreak} _
+ * @param {Parents | undefined} _1
+ * @param {State} state
+ * @returns {string}
+ */
+export function thematicBreak(_, _1, state) {
+  const value = (
+    checkRule(state) + (state.options.ruleSpaces ? ' ' : '')
+  ).repeat(checkRuleRepetition(state))
+
+  return state.options.ruleSpaces ? value.slice(0, -1) : value
+}