Add way to copy last Buddy (assistant) message to clipboard

Problem

There's no way to quickly copy the last Buddy assistant response to the clipboard. The primary use case is pasting Buddy's output back into the Claude Code command line as part of a follow-up prompt — e.g. when Buddy suggests something and you want to reference or refine it in your next message.

Currently the only options are manual text selection in the terminal (error-prone with long or wrapped responses) or digging through conversation JSON files after the session ends.

Proposed Solution

Add one or both of:

1. A keybinding action — e.g. buddy:copyLastMessage bound to a shortcut like Ctrl+Shift+B, which copies the last Buddy response (markdown source) to the system clipboard.

1. A built-in command — e.g. /buddy copy (extending the existing /buddy command family) that copies the last Buddy response to clipboard and confirms with a short message.

1. A paste-into-prompt shortcut — e.g. buddy:pasteToPrompt that inserts the last Buddy message directly into the current input line, skipping the clipboard entirely.

Considerations

• Format: Copy raw markdown to preserve code blocks and formatting. An optional --plain flag could strip markdown.
• Scope: "Last message" means the most recent Buddy turn. Could extend to --all for full conversation.
• Hook access: Exposing Buddy message content in Stop hook input would let users build custom post-response automations.

Alternatives Considered

• Manual terminal text selection — unreliable for long or wrapped output
• Reading conversation JSON from ~/.claude/ — not real-time, requires parsing
• Custom skills/commands — these don't have access to conversation history