feat(website): add Markdown table answers

[Natsummerance]

Summary

• Add dedicated localized answer pages for the high-intent Markdown-tables task in English, Simplified Chinese, Traditional Chinese, and Japanese.
• Cover the documented table designer plus Excel and CSV paste conversion while preserving source-file and save boundaries.
• Expand root/localized AI corpora and sitemap from 36 to 40 canonical URLs.
• Extend browser smoke and clean-network production checks to all 40 routes.

Approvals

• SEO intent: 9.89
• Content accuracy: 9.83
• Release engineering: 9.79
• Final decision meeting: 9.84 (markdown_tables_approval.json)
• The approval records the $dbs-content-system question/concept/solution units and the $dbs-spread five-theory transmission review.

Validation

• npm run verify:release: green across 40 canonical URLs.
• Browser smoke: 40 / 40 routes passed, including four new Markdown-tables pages; zero failures and zero broken images.
• Production workflow now covers all four localized table route variants.