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/@astrojs/markdown-remark/dist/frontmatter.d.ts

@@ -0,0 +1,20 @@
+export declare function isFrontmatterValid(frontmatter: Record<string, any>): boolean;
+export declare function extractFrontmatter(code: string): string | undefined;
+export interface ParseFrontmatterOptions {
+    /**
+     * How the frontmatter should be handled in the returned `content` string.
+     * - `preserve`: Keep the frontmatter.
+     * - `remove`: Remove the frontmatter.
+     * - `empty-with-spaces`: Replace the frontmatter with empty spaces. (preserves sourcemap line/col/offset)
+     * - `empty-with-lines`: Replace the frontmatter with empty line breaks. (preserves sourcemap line/col)
+     *
+     * @default 'remove'
+     */
+    frontmatter: 'preserve' | 'remove' | 'empty-with-spaces' | 'empty-with-lines';
+}
+export interface ParseFrontmatterResult {
+    frontmatter: Record<string, any>;
+    rawFrontmatter: string;
+    content: string;
+}
+export declare function parseFrontmatter(code: string, options?: ParseFrontmatterOptions): ParseFrontmatterResult;