Add @nav parallel route slots for all major routes to prevent game names
from persisting when navigating between different sections of the app.
- Add @nav/page.tsx (home)
- Add @nav/create/page.tsx (create page)
- Add @nav/guide/page.tsx (guide page)
- Add @nav/games/page.tsx (games listing)
- Keep @nav/games/matching/page.tsx (Memory Pairs game)
- Keep @nav/games/memory-quiz/page.tsx (Memory Lightning game)
- Add comprehensive e2e test covering navigation persistence scenarios
All non-game routes return null (no game name in mini nav).
Only game routes show their specific game names.
Fixes issue where navigating Game → Guide → Games would show stale game name.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
3fa314aaa5