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/mdn-data/css/syntaxes.schema.json

@@ -0,0 +1,15 @@
+{
+  "type": "object",
+  "additionalProperties": {
+    "type": "object",
+    "additionalProperties": false,
+    "required": [
+      "syntax"
+    ],
+    "properties": {
+      "syntax": {
+        "type": "string"
+      }
+    }
+  }
+}