Expand QR business guide

[rrih]

Summary

• Expanded the existing QR code business guide with destination-selection guidance, a launch checklist, and UTM tracking advice.
• Updated the article metadata and regenerated the matching blog OG image, sitemap, and service worker.
• Left ad density, AdSense settings, tool logic, DNS, secrets, and existing draft PR files unchanged.

Selected action

• Type: auto-pr existing article/page expansion under https://rrih.github.io/.
• Rationale: GSC latest snapshot shows /blog/generate-qr-codes-for-your-business/ with impressions and 0 clicks, while open draft PRs Improve animation generator CTR copy #26 and Add overtime pay calculator #28 are clean review-waiting drafts. This strengthens practical content and the QR Generator path without regulated formulas or ad changes.

Expected KPI impact

• Better post-click usefulness for QR business queries.
• More internal movement from the guide into /tools/qr-generator/.
• Fresher sitemap/metadata for the updated article.

Verification

• bun test
• bun --bun tsc --noEmit
• bun run lint (pass with existing 9 warnings)
• bun run build
• bun run dev-check
• Browser check at http://localhost:3333/blog/generate-qr-codes-for-your-business/: desktop 1280px and mobile 390px showed the new sections, QR tool link, no horizontal overflow, and no console errors.

References #15