Fixes deep-link close to preserve browser history state and adds comprehensive integration tests for the navigation history feature, covering App component and useDeepLink hook behavior.
Fusion-Task-Id: FN-3344
- Add isolate: true to vitest configs for safe parallel test execution
- Simplify engine test script from 7 sequential runs to single parallel run
- Fix TypeScript type errors in Column, Board, WorktreeGroup, and App components
- Fix board-mobile test to match current TaskCard tap behavior
- Relax App deep-link test to handle React Strict Mode behavior
- Extract modal manager, app settings, deep-link handling, favorites, and auth onboarding into dedicated hooks
- Rewire App.tsx to consume the new hooks and reduce component-level state/effect complexity
- Preserve favorite-toggle error toast behavior in the updated favorites wiring
- Add hook-level test coverage for modal manager, app settings, deep links, favorites, and auth onboarding flows