- Add tokio async runtime for concurrent pane command execution
- Change from Rc to Arc for thread-safe reference counting
- Implement pane readiness checking before command execution
- Add child process monitoring to detect command completion
- Commands within a pane execute sequentially, multiple panes run in parallel
- Store JoinHandles and implement Drop to abort tasks on cleanup
- Session attachment no longer blocks on pane command execution
- Add Send + Sync + 'static bounds to Runner trait

- Replace intrusive echo test with PID-based readiness check
- Check if pane has no child processes to determine readiness
- Add wait_for_tasks method to ensure tasks complete before exit
- Block on task completion when using --skip-attach
- Add debug logging for pane readiness and command execution
- Add test YAML files to verify parallel/sequential execution

Verified working: Commands within each pane execute sequentially while
multiple panes run in parallel.

- Remove overly verbose debug logs
- Keep useful debug logs for -vvvv troubleshooting
- Remove test YAML files from repository root

- Change from 50 attempts × 100ms (5s) to 60 second timeout
- Increase poll interval to 200ms to reduce overhead
- Add elapsed time logging for better debugging
- Prevents commands from being skipped when shell startup is slow

- Replace PID-based readiness check with output stability detection
- Capture pane output twice with 200ms delay and compare
- Pane is ready when output stops changing (stabilized)
- Works correctly with slow shell initialization (direnv, devenv, plugins)
- PID check now only used for command completion detection
- Non-intrusive: no test commands or key presses sent to pane

- Always wait for async tasks to finish sending commands before CLI exits
- Previously tasks were aborted when attaching (not using --skip-attach)
- Commands are sent via tmux send-keys within async tasks
- If tasks abort, commands never get sent to panes
- Now waits for all tasks whether using --skip-attach or not

- attach-session blocks, keeping CLI alive while user is in session
- switch-client returns immediately, so must wait for tasks first
- skip-attach exits immediately, so must wait for tasks first
- This allows instant attach while ensuring commands execute

- Move task waiting logic into explicit branches for attach and switch-client scenarios
- Ensure tasks are awaited after switch-client and when skipping attach, aligning CLI exit behavior
- Remove redundant conditional block to streamline control flow
- Add comments clarifying when tasks are awaited versus run in background