fix(playable): close release validation lifecycle gaps

script/playable_soak.sh

@@ -22,6 +22,8 @@ set -euo pipefail
 set +x
 cd "$(dirname "$0")/.."
 repo="$PWD"
+process_cleanup_grace_seconds=15 # Allow the child runner's 10-second cleanup to finish.
+source script/playable_process_cleanup.sh
 app="${MT_PLAYABLE_APP:-}"
 config=""
 output=""
@@ -152,8 +154,11 @@ run_one() { # name suite timeout
   if [ -n "$assets" ]; then args+=(--assets "$assets"); fi
   if [ -n "$serverlist" ]; then args+=(--serverlist "$serverlist"); fi
   set +e
-  bash script/run_client_gate.sh "${args[@]}" </dev/null
+  bash script/run_client_gate.sh "${args[@]}" </dev/null &
+  child_pid=$!
+  wait "$child_pid"
   code=$?
+  child_pid=""
   set -e
   if [ "$code" -eq 124 ]; then timed_out=1; fi
   if [ "$code" -ne 0 ] && [ "$run_suite" = "playable" ]; then stop_reason="$name exit $code"; fi