fix(playable): close release validation lifecycle gaps

script/playable_process_cleanup.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+# Sourced by runners. Only signal children whose PIDs this runner still owns.
+# Clear each PID immediately after wait, so EXIT cannot signal a reused PID.
+child_pid=""
+redactor_pid=""
+sampler_pid=""
+proxy_pid=""
+
+cleanup_playable_processes() {
+  local status=$? pid round alive
+  trap - EXIT
+  trap '' HUP INT TERM
+  for pid in "$child_pid" "$redactor_pid" "$sampler_pid" "$proxy_pid"; do
+    if [ -n "$pid" ]; then kill -TERM "$pid" 2>/dev/null || true; fi
+  done
+  for ((round=0; round<${process_cleanup_grace_seconds:-10}; round++)); do
+    alive=0
+    for pid in "$child_pid" "$redactor_pid" "$sampler_pid" "$proxy_pid"; do
+      if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then alive=1; fi
+    done
+    [ "$alive" -eq 1 ] || break
+    sleep 1
+  done
+  for pid in "$child_pid" "$redactor_pid" "$sampler_pid" "$proxy_pid"; do
+    if [ -n "$pid" ]; then
+      kill -KILL "$pid" 2>/dev/null || true
+      wait "$pid" 2>/dev/null || true
+    fi
+  done
+  if [ -n "${fifo:-}" ] && [ -p "$fifo" ]; then rm -f "$fifo"; fi
+  return "$status"
+}
+
+trap cleanup_playable_processes EXIT
+trap 'exit 129' HUP
+trap 'exit 130' INT
+trap 'exit 143' TERM