Reliable loop messaging: msg-loop.sh + hardened ping_session (retry submit)

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>

cc-ci-plan/launch.sh

@@ -142,11 +142,21 @@ stop_loops() {
   done
 }
 
-# Wake a loop by typing a one-line message into its tmux session (queues if mid-turn).
+# Wake a loop by typing a message into its tmux session and SUBMITTING it. A single Enter after a
+# long `send-keys -l` is often swallowed while the TUI ingests the paste (text left unsent in the
+# input box), so retry Enter/C-m until the message's leading text is no longer in the input box.
 ping_session() {
-  local s="$1" msg="$2"
+  local s="$1" msg="$2" prefix i
   session_alive "$s" || return 0
-  tmux send-keys -t "$s" -l -- "$msg" 2>/dev/null && { sleep 0.3; tmux send-keys -t "$s" Enter 2>/dev/null; }
+  prefix="${msg:0:28}"
+  tmux send-keys -t "$s" -l -- "$msg" 2>/dev/null || return 0
+  sleep 0.5
+  for i in 1 2 3 4 5; do
+    tmux send-keys -t "$s" Enter 2>/dev/null
+    sleep 1
+    tmux capture-pane -pt "$s" 2>/dev/null | tail -4 | grep -qF -- "$prefix" || return 0  # submitted
+    tmux send-keys -t "$s" C-m 2>/dev/null; sleep 0.5
+  done
 }
 
 # A loop can stall ALIVE on a usage/spend-limit notice: the claude process stays up (so the