fix(shell): remove runtime early-exit pipe hazards

packages/mosaic/framework/tools/tmux/send-message.sh

@@ -110,7 +110,7 @@ for attempt in $(seq 1 $((RETRIES + 1))); do
   sleep 1.2
   pane=$("${tmux_cmd[@]}" capture-pane -t "$EFFECTIVE_TARGET" -p 2>/dev/null)
 
-  if printf '%s' "$pane" | grep -qF "$QUEUED_RE"; then
+  if grep -qF "$QUEUED_RE" <<<"$pane"; then
     status="queued"; break
   fi
   # Locate the REPL input box (prompt glyph). If we cannot see it, we have NO
@@ -121,7 +121,7 @@ for attempt in $(seq 1 $((RETRIES + 1))); do
   fi
   # Input box located AND still carrying our tail => unsubmitted draft. Flush + retry.
   # (Submitted messages scroll up into history; a draft stays on the ❯ line.)
-  if [ -n "$snippet" ] && printf '%s' "$promptline" | grep -qF "$snippet"; then
+  if [ -n "$snippet" ] && grep -qF "$snippet" <<<"$promptline"; then
     status="draft"; continue
   fi
   # Input box located AND clear of our tail => positively submitted. This is the