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/deterministic-object-hash/dist/isPlainObject.js

@@ -0,0 +1,27 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const objConstructorString = Function.prototype.toString.call(Object);
+function isPlainObject(value) {
+    //base object
+    if (typeof value !== 'object' ||
+        value === null ||
+        Object.prototype.toString.call(value) !== '[object Object]') {
+        return false;
+    }
+    //get the prototype
+    const proto = Object.getPrototypeOf(value);
+    //no prototype === all good
+    if (proto === null) {
+        return true;
+    }
+    //has own prop 'constructor'
+    if (!Object.prototype.hasOwnProperty.call(proto, 'constructor')) {
+        return false;
+    }
+    // validate that the constructor is `Object`
+    return (typeof proto.constructor === 'function' &&
+        proto.constructor instanceof proto.constructor &&
+        Function.prototype.toString.call(proto.constructor) === objConstructorString);
+}
+exports.default = isPlainObject;
+;