docs: add generateStaticParams section to Cache Components migration guide
- Document that generateStaticParams remains valid with links to API and dynamic-routes Cache Components docs
- Note empty-array migration and link to empty-generate-static-params message
- Add before/after example (return [] vs sample param)
- Explain ◐ vs ○ build output with links to public-pages PPR section and glossary
Made-with: Cursor