Previously the back button left the dashboard page entirely because
useNavigationHistory was only enabled for mobile viewports. Now it's
enabled for all viewports — desktop and mobile — so the browser back
button dismisses modals and reverts view changes within the SPA.
Changes:
- Enable useNavigationHistory for desktop (enabled: true instead of enabled: isMobile)
- Remove all isMobile ? historyAwareHandler : plainHandler ternaries
- Always use navigation-aware handlers (openDetailTask, openSettingsWithNav, etc.)
- Update JSDoc to reflect desktop support
