Reported in discussion #20.

The prompt input is missing muscle-memory keys that long-time terminal users reach for:

Must-have:

• Home / Ctrl+A — cursor to start of line
• End / Ctrl+E — cursor to end of line
• Ctrl+U — kill from cursor to start of line

Should-have:

• Ctrl+W — delete previous word
• Ctrl+K — kill from cursor to end of line
• Alt+B / Alt+F — jump word backward / forward
• Alt+Backspace — delete previous word (alt form of Ctrl+W)

Land alongside the existing ↵ / ⇧↵ / ↑↓ vocabulary documented in the RFC.