Optimise SEO

• IS: crawlability, metadata, structured data, canonicals, redirects, hreflang, Core Web Vitals, programmatic SEO, security/privacy headers, and error-page status behaviour for Next.js App Router apps.
• IS NOT: visual redesigns or layout changes (use ui-design), page-level UI quality review (use ui-audit), or making a site readable by AI agents via llms.txt and agent protocols (use agent-ready-audit).

Allowed file surface: metadata, structured data, semantic HTML, internal links, alt text, app/sitemap.ts, app/robots.ts, next.config.ts redirects and headers, error pages, performance tuning. Never touch component styling or layout.

Workflow

Copy and track this checklist:

SEO progress:
- [ ] Step 1: Inventory routes and decide index intent per route
- [ ] Step 2: Fix crawl/index foundations (sitemap, robots, canonicals, redirects, status codes)
- [ ] Step 3: Implement metadata + structured data
- [ ] Step 4: Improve semantics, internal links, and Core Web Vitals
- [ ] Step 5: Validate with references/seo-checklist.md and report evidence