- App struct with full state (lists, tasks, focus, popups, DB)
- Tab cycles focus: Tabs -> TaskList -> Detail -> Tabs
- Left/Right arrows switch lists when focus on Tabs
- Up/Down navigate tasks (TaskList) or scroll (Detail)
- Alt+Up/Down reorder tasks with position persistence
- n: create new list or task, d: delete, e: edit title
- Enter on Detail opens DatePicker popup
- InputPopup with full text editing (navigation, insert, delete)
- ConfirmDelete popup before destructive actions
- DatePicker adjusts draft_date with Up/Down
- main.rs: terminal setup, event loop, raw mode, alternate screen