- Current page in nav is now a span instead of a link (no self-links)
- Logo links to home page, except when already on home
- Use aria-current="page" with accent underline for current page indicator
- Extract logo_content, logo_inner, and nav_item helper components
- Update CSS to target both a and span elements in .shop-nav
This follows WCAG accessibility guidelines - links that point to
the current page are confusing for screen reader users.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>