- Create StatusBar component with 30px fixed height
- Position at bottom of app layout with proper flex column structure
- Add placeholders for vim mode (left) and sync status (right)
- Reorganize App layout to accommodate status bar below main content
Add complete sidebar implementation with:
- ProjectTree model using arena allocator for hierarchical projects
- FilterState model for global filter state management
- Sidebar view with independent scrollable sections
- Project tree with expand/collapse functionality
- Tag selection with toggle support
- Observable filter state shared across components