tmux `send-keys -l <long msg>` often leaves the text UNSENT in the input box (the
immediate Enter is swallowed while the TUI ingests the paste). Both now type the
message then retry Enter/C-m until the leading text is no longer in the input box
(= submitted) or a bounded loop gives up.
- msg-loop.sh: standalone reliable messenger for orchestrator use.
- launch.sh ping_session: same retry-submit (loads on next watchdog restart).
Live-tested: delivered first try.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>