Add promote_running to CompanionManager: scans STARTING companions and moves
any that have stayed alive at least their startsecs window to RUNNING, logging
the pid and returning the promoted ones. Companions that die inside the window
are left to reaping.
Add tests for promotion after the window, too-early no-op, and non-STARTING.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add reap_processes to CompanionManager: drains waitpid(WNOHANG), matches each
dead pid back to its companion, and records the exit via _record_exit (signal
number or exit code, exited_at, exit_count) while freeing the pid. Returns the
reaped companions; the restart decision stays with the run loop.
Add tests for exit-code, signal, and no-children cases.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Child calls _redirect_output after env setup: each configured log path is
opened append-mode and dup2'd onto fd 1/2. None/inherit keeps the inherited
fd; stderr stdout shares stdout's fd. Rotation stays external.
Add tests for inherit, append flags, file dup2, and stderr-to-stdout.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
