Add author archive pages displaying all posts by a specific author, following
the existing tag pages pattern. Author names in post headers are now clickable
links that navigate to the author's page.
Changes:
- Add by_authorName index to posts table (convex/schema.ts)
- Add getAllAuthors and getPostsByAuthor queries (convex/posts.ts)
- Create AuthorPage.tsx component with list/cards view toggle
- Add /author/:authorSlug route (src/App.tsx)
- Make authorName clickable in Post.tsx for posts and pages
- Add author link and page styles (src/styles/global.css)
- Add author pages to sitemap (convex/http.ts)
- Update documentation: files.md, TASK.md, changelog.md, changelog-page.md
- Save implementation plan to prds/authorname-blogs.md
