Changes

• Replaced the root index.html with index.md, switched it to the page layout, and moved the About content there so the homepage now shows the bio instead of the post feed.
• Removed the old _tabs/about.md entry and added _tabs/blog.md that points at /blog/, uses the new blog layout, and sits right after Home in the nav.
• Introduced _layouts/blog.html by copying Chirpy’s home layout and adding a fallback for when pagination isn’t running; the Blog tab now reproduces the old home feed.
• Tweaked _tabs/categories.md, _tabs/tags.md, and _tabs/archives.md order fields so navigation ordering stays consistent after inserting the Blog tab.
• Dropped the unused paginate setting from _config.yml because pagination now lives only in the dedicated blog layout, avoiding warnings during jekyll build.