feat: implement marketing pages, core QR tools, and SEO infrastructure for QR Master

src/app/(main)/(marketing)/bulk-qr-code-generator/page.tsx

@@ -176,6 +176,13 @@ const howToSchema = {
   '@type': 'HowTo',
   '@id': 'https://www.qrmaster.net/bulk-qr-code-generator#howto',
   name: 'How to generate bulk QR codes from a spreadsheet',
+  datePublished: '2024-01-01',
+  dateModified: '2025-06-01',
+  author: {
+    '@type': 'Person',
+    name: 'Timo Knuth',
+    url: 'https://www.qrmaster.net/authors/timo',
+  },
   description:
     'Upload a spreadsheet, map the title and content columns, preview the batch, then generate and download the QR codes.',
   totalTime: 'PT10M',
@@ -380,6 +387,12 @@ export default function BulkQRCodeGeneratorPage() {
           />
         </div>
 
+        <div className="container mx-auto max-w-5xl px-4 pb-2 sm:px-6 lg:px-8">
+          <p className="text-xs text-gray-400 italic px-1">
+            By Timo Knuth, QR Master · Last updated: June 2025
+          </p>
+        </div>
+
         <div className="container mx-auto max-w-5xl px-4 pb-8 sm:px-6 lg:px-8">
           <FAQSection items={faqItems} title="Bulk QR questions" />
         </div>