feat(tui): session scratchpad `<leader>w` to store notes, todos, system prompt extensions etc...

[spoons-and-mirrors]

Summary

This feature allows users to maintain session-specific notes, todos, or system prompt extensions that persist in the session and are visible to the agent at all time. It improves workflow organization and enables richer, context-aware agent interactions.

Features

• Integrates a modal scratchpad editor in the TUI, accessible via a new keybinding (<leader>w).
• Scratchpad content is shared with the agent as a system message for each session.

[adamdotdevin]

interesting idea, need to think about this a bit; visually, is it easy to remove the indentation and second border?

[spoons-and-mirrors]

Is this what you have in mind @adamdotdevin ?