Next.js route-level layouts provide Sidebar + gradient background
automatically for all sub-pages. Individual pages no longer need
their own wrapper divs or Sidebar imports.
- learn/layout.tsx: Sidebar + purple gradient for all learning pages
- parent/layout.tsx: Same for all parent portal pages
- LearnLayout.tsx: Reusable component for other pages
- Fixed broken <LearnLayout>}> artifacts from previous refactoring
- Removed duplicate Sidebar/wrapper code from 9 sub-pages
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>