fix(auth): harden diagnostic cleanup races

tools/tht/internal/compose/process_termination.go

@@ -0,0 +1,41 @@
+package compose
+
+import "time"
+
+// terminateWindowsProcess reports a reap failure only when the process has not exited within the
+// final bound. taskkill and Process.Kill can both race with a child that has already been reaped.
+func terminateWindowsProcess(
+	done <-chan error,
+	terminateTree func() error,
+	terminateDirect func() error,
+	bound time.Duration,
+) error {
+	if processReaped(done) {
+		return nil
+	}
+	_ = terminateTree()
+	if processReaped(done) {
+		return nil
+	}
+	_ = terminateDirect()
+	if processReaped(done) {
+		return nil
+	}
+	timer := time.NewTimer(bound)
+	defer timer.Stop()
+	select {
+	case <-done:
+		return nil
+	case <-timer.C:
+		return ErrProcessReap
+	}
+}
+
+func processReaped(done <-chan error) bool {
+	select {
+	case <-done:
+		return true
+	default:
+		return false
+	}
+}