Move nav to shared Header in layout.tsx, remove inline header/footer
from page.tsx. Add UserMenu, SpaceSwitcher, and updated AppSwitcher.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Adds the unified rStack app switcher with pastel badges, emoji icons,
and categorized navigation across all 17 rStack apps.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>