18c6cf5406
Previous attempts used a separate NavBar component (nav-bar.vue).
Even with styles in App.vue's global scope, the component wrapper
created an abstraction layer that prevented the nav from rendering.
Now the nav markup, logic, and styles are all in App.vue directly:
- <div class="app-nav"> renders inline in App.vue template
- .app-nav{display:none} on mobile, display:flex on desktop (>=1024px)
- No component boundary, no data-v-xxxxx scoping issues
- Deleted components/nav-bar.vue