Introduce one key-hint grammar across every view: bold key, dim label,
priority-ordered hints that drop from the end instead of ellipsizing.
The month footer becomes a single split status bar with a friendly
selected date, the '?' mega-line becomes a real keyboard shortcut
panel, and the editor, agenda, search, picker, detail, and delete
frames share the same chips. Notifications carry check/warning marks.
Adds a live PTY smoke test covering view interaction and terminal
state restoration on q and Ctrl-C exits.
