feat(driver): add TapSelector and make mock WaitForIdle honor duration

Real maestro driver will resolve selectors itself rather than
forcing the runner to look up coordinates from the hierarchy. Mock
now waits the requested duration so tests don't busy-spin and
starve the SDK fixture goroutine.

internal/driver/mock/mock.go

@@ -14,6 +14,7 @@ const (
 	ActionLaunch      ActionKind = "launch"
 	ActionTerminate   ActionKind = "terminate"
 	ActionTap         ActionKind = "tap"
+	ActionTapSelector ActionKind = "tap_selector"
 	ActionInputText   ActionKind = "input_text"
 	ActionHierarchy   ActionKind = "hierarchy"
 	ActionScreenshot  ActionKind = "screenshot"
@@ -26,6 +27,7 @@ type Action struct {
 	BundleID   string
 	ClearState bool
 	X, Y       int
+	Selector   string
 	Text       string
 	Idle       time.Duration
 }
@@ -98,6 +100,14 @@ func (d *Driver) Tap(ctx context.Context, x, y int) error {
 	return nil
 }
 
+func (d *Driver) TapSelector(ctx context.Context, selector string) error {
+	if err := d.failure(ActionTapSelector); err != nil {
+		return err
+	}
+	d.record(Action{Kind: ActionTapSelector, Selector: selector})
+	return nil
+}
+
 func (d *Driver) InputText(ctx context.Context, text string) error {
 	if err := d.failure(ActionInputText); err != nil {
 		return err
@@ -131,7 +141,17 @@ func (d *Driver) WaitForIdle(ctx context.Context, duration time.Duration) error
 		return err
 	}
 	d.record(Action{Kind: ActionWaitForIdle, Idle: duration})
-	return nil
+	if duration <= 0 {
+		return nil
+	}
+	timer := time.NewTimer(duration)
+	defer timer.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-timer.C:
+		return nil
+	}
 }
 
 func (d *Driver) Health(ctx context.Context) (driver.Health, error) {