fix(testrun): seam preflight so iOS routing tests pass on CI without xcrun

internal/testrun/driver.go

@@ -69,6 +69,10 @@ func resolveIOSTarget(ctx context.Context, options Options, stdout io.Writer) (O
 	return options, nil
 }
 
+// preflight is a seam so routing tests exercise driver construction without the
+// host-readiness checks (xcrun, java) that are absent on a Linux CI runner.
+var preflight = Preflight
+
 // newDeviceDriver constructs the physical-device iOS driver and its cleanup. A
 // seam so routing tests assert the resolved identifiers reach DeviceOptions
 // without building or spawning a real runner.
@@ -86,7 +90,7 @@ var newDeviceDriver = func(ctx context.Context, options ioscompanion.DeviceOptio
 // is driven runner-only over a usbmux tunnel. Android uses the JVM sidecar,
 // which is extracted, spawned, and dialed.
 func buildDriver(ctx context.Context, options Options, stdout io.Writer) (driver.DeviceDriver, func(), error) {
-	if err := Preflight(ctx, options.Platform); err != nil {
+	if err := preflight(ctx, options.Platform); err != nil {
 		return nil, nil, err
 	}
 	if options.Platform == "web" {

internal/testrun/driver_test.go

@@ -16,6 +16,7 @@ import (
 type stubDeviceDriver struct{ driver.DeviceDriver }
 
 func TestBuildDriverRoutesPhysicalIOSToDeviceDriver(t *testing.T) {
+	stubPreflight(t)
 	original := newDeviceDriver
 	t.Cleanup(func() { newDeviceDriver = original })
 
@@ -51,6 +52,7 @@ func TestBuildDriverRoutesPhysicalIOSToDeviceDriver(t *testing.T) {
 }
 
 func TestBuildDriverSurfacesDeviceConstructionError(t *testing.T) {
+	stubPreflight(t)
 	original := newDeviceDriver
 	t.Cleanup(func() { newDeviceDriver = original })
 	newDeviceDriver = func(context.Context, ioscompanion.DeviceOptions) (driver.DeviceDriver, func(), error) {
@@ -63,6 +65,15 @@ func TestBuildDriverSurfacesDeviceConstructionError(t *testing.T) {
 	}
 }
 
+// stubPreflight bypasses the host-readiness checks so routing tests exercise
+// driver construction on a Linux CI runner that lacks xcrun/java.
+func stubPreflight(t *testing.T) {
+	t.Helper()
+	original := preflight
+	t.Cleanup(func() { preflight = original })
+	preflight = func(context.Context, string) error { return nil }
+}
+
 func swapIOSResolveSeams(t *testing.T) {
 	t.Helper()
 	origTarget, origDevice, origEnsure := iosResolveTarget, iosResolveDevice, iosEnsureSimulator