ci cross-platform fix: make gateway reload/signal handling windows-safe with build-tagged helpers

cmd/clawgo/signals_windows.go

@@ -0,0 +1,13 @@
+//go:build windows
+
+package main
+
+import "os"
+
+func gatewayNotifySignals() []os.Signal {
+	return []os.Signal{os.Interrupt}
+}
+
+func isGatewayReloadSignal(sig os.Signal) bool {
+	return false
+}