app.sh: forward SIGHUP to child instead of SIGTERM to process group

dogecoin-qt was being killed abruptly on container stop. Send SIGHUP
directly to the child process for a graceful shutdown instead of
SIGTERM'ing the whole process group.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EzpyzTGGvRC1FdaJkEHYyP

app/app.sh

@@ -16,7 +16,7 @@ TERM_handler() {
     if [ ${PID} -ne 0 ]; then
         ps -ef --forest
         CHILDS=$(pgrep -P "${PID}")
-        kill -SIGTERM -"${PID}"
+        kill -SIGHUP $CHILDS
         for i in $CHILDS; do
           wait $i
         done