Summary

Multiple SEO issues in VitePress documentation site:

1. titleTemplate bug — literal %s in <title> instead of actual page title (VitePress v1.6.4 uses :title, not %s)
2. cleanUrls missing — mixed .html / no-extension URLs in sitemap and links
3. Missing <link rel="canonical"> — no canonical tags on any page
4. Sitemap missing lastmod — no lastmod dates in sitemap.xml
5. Keywords missing — no <meta name="keywords"> on ~72 pages

Fix

• Update docs/.vitepress/config.mts: titleTemplate, cleanUrls, canonical, sitemap lastmod, ignoreDeadLinks
• Add titleTemplate: false to home page frontmatter
• Add keywords meta to all .md and .md.in files