9e96e70995
* feat(cli): /prompt — compose your next prompt in $EDITOR Adds /prompt (alias /compose): opens $VISUAL/$EDITOR on a temp markdown file so you can hand-edit a multi-line prompt, then sends the saved buffer as the next agent turn. Text after the command pre-seeds the buffer; an empty save cancels. Reuses the one-shot _pending_agent_seed the interactive loop already consumes (same mechanism as /blueprint), so no changes to the input event loop or message pipeline. CLI-only. * feat(tui): /prompt slash command opens $EDITOR (parity with CLI) The TUI already opens $EDITOR via Ctrl+G (openEditor), but had no /prompt slash command like the classic CLI. Wire openEditor into the slash handler context and register /prompt (alias /compose) to call it; inline text after the command is dropped into the composer first so it carries into the editor, matching the CLI's /prompt <text>.