Harvested from PR #2733 by @idling11.
Adds richer update_plan artifact fields for grounded Plan-mode review, renders them in the transcript and Plan confirmation prompt, and carries them through /relay, fork-state, and saved-session replay.
Verification: cargo test -p codewhale-tui --bin codewhale-tui --locked plan_ -- --nocapture
Verification: cargo test -p codewhale-tui --bin codewhale-tui --locked relay_slash_command_routes_to_session_relay_instruction -- --nocapture
Verification: cargo clippy -p codewhale-tui --locked -- -D warnings
Co-authored-by: idling11 <8055620+idling11@users.noreply.github.com>
Harvested from #2407 with thanks to @axobase001.
Adds a first-time macOS Python FAQ and completes the virtualenv flow with the final run command.
Fixes#2351.