- FilterBar component with text search, label chips, due date and priority dropdowns
- "/" keyboard shortcut and toolbar button to toggle filter bar
- Keyboard card navigation with J/K/H/L keys, Enter to open, Escape to clear
- Focus ring on keyboard-selected cards with auto-scroll
- Desktop notifications for due/overdue cards via tauri-plugin-notification
- CommentsSection component with add/delete and relative timestamps
- Filtered card count display in column headers
- TopBar: call closeBoard() before navigating back to prevent data loss
- board-store: guard debouncedSave against race condition when board is
closed during an in-flight save
- board-store: add missing updatedAt to setColumnWidth
- useKeyboardShortcuts: remove duplicate Ctrl+K handler that prevented
command palette from toggling closed
- AttachmentSection: wire up Tauri file dialog for adding attachments
with link/copy mode support
