e5316be454
PR #48 closed; treat the implementation as starting from main, where no tmux integration exists yet. The PRD now describes the full design (including the `_in_tmux` detection + helper scaffolding) as fresh work. Sized into 4 chunks: `claude_docker_argv` refactor → tmux helpers + pane state + `_attach_to_bottle` dispatch → new-agent flow → stop + indicator. Same design as before — opt-in by `\$TMUX`, split-window-then- respawn, falls back to handoff on tmux failure or missing binary. No external references to PR #48.