libtmux:respawn-pane

Restart PANE's process and return a COMMAND-OUTCOME. KILL explicitly replaces a running process; otherwise tmux requires it to have exited. Omit COMMAND and SHELL-COMMAND to reuse the previous command. Explicit argv, shell text, literal CWD and ENVIRONMENT follow NEW-WINDOW. OBSERVE returns a replacement pane through OUTCOME-VALUE; its earlier capture stays unchanged. The process may exit before observation. Signals STALE-TARGET or an operational condition; never retries an uncertain restart.