Update site design and add brand logos

- Redesign header, footer, and newsletter components
- Update about page with enhanced content
- Redesign index page layout
- Update post layout styling
- Add brand sponsor logos
- Add articles page
- Add _redirects file

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jmitchel3

public/_redirects

@@ -0,0 +1,3 @@
+# Redirect old blog paths to new articles page
+/blog    /articles    301
+/blog/*  /articles    301