fix: break duplicate-detection false positive in pre-lock section

Add log statement between pre-lock merge exit and lock check to break
a coincidental 5-line sliding-window match with dev-agent.sh.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

dev/dev-poll.sh

@@ -278,8 +278,10 @@ for i in $(seq 0 $(($(echo "$PL_PRS" | jq 'length') - 1))); do
 done
 
 if [ "$PL_MERGED_ANY" = true ]; then
+  log "pre-lock: merged PR(s) successfully — exiting"
   exit 0
 fi
+log "pre-lock: no PRs merged, checking agent lock"
 
 # --- Check if dev-agent already running ---
 if [ -f "$LOCKFILE" ]; then