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/clsx/clsx.d.ts

@@ -0,0 +1,10 @@
+declare namespace clsx {
+	type ClassValue = ClassArray | ClassDictionary | string | number | bigint | null | boolean | undefined;
+	type ClassDictionary = Record<string, any>;
+	type ClassArray = ClassValue[];
+	function clsx(...inputs: ClassValue[]): string;
+}
+
+declare function clsx(...inputs: clsx.ClassValue[]): string;
+
+export = clsx;