fix: honor context cancel during bridge reconnect backoff

cmd/clawgo/main.go

@@ -350,7 +350,12 @@ func runNode(cfg NodeConfig) error {
 		client, err := connectBridge(cfg.BridgeAddr)
 		if err != nil {
 			logf("bridge connect failed: %v", err)
-			time.Sleep(backoff)
+			if err := sleepContext(ctx, backoff); err != nil {
+				if mdnsCleanup != nil {
+					mdnsCleanup()
+				}
+				return nil
+			}
 			if backoff < 15*time.Second {
 				backoff *= 2
 				if backoff > 15*time.Second {
@@ -482,7 +487,12 @@ func runNode(cfg NodeConfig) error {
 			}
 			return nil
 		}
-		time.Sleep(backoff)
+		if err := sleepContext(ctx, backoff); err != nil {
+			if mdnsCleanup != nil {
+				mdnsCleanup()
+			}
+			return nil
+		}
 		if backoff < 15*time.Second {
 			backoff *= 2
 			if backoff > 15*time.Second {

cmd/clawgo/sleep.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"context"
+	"time"
+)
+
+func sleepContext(ctx context.Context, d time.Duration) error {
+	t := time.NewTimer(d)
+	defer t.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-t.C:
+		return nil
+	}
+}

cmd/clawgo/sleep_test.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestSleepContextCanceledReturnsCanceled(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	err := sleepContext(ctx, 30*time.Second)
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("sleepContext(canceled, 30s) = %v, want context.Canceled", err)
+	}
+}
+
+func TestSleepContextCancelDuringWait(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() {
+		done <- sleepContext(ctx, 30*time.Second)
+	}()
+	cancel()
+
+	var err error
+	select {
+	case err = <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("sleepContext did not return after cancel")
+	}
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("sleepContext canceled mid-wait = %v, want context.Canceled", err)
+	}
+}
+
+func TestSleepContextCompletesWhenContextStaysOpen(t *testing.T) {
+	err := sleepContext(context.Background(), time.Millisecond)
+	if err != nil {
+		t.Fatalf("sleepContext(background, 1ms) = %v, want nil", err)
+	}
+}