fix: select component reactivity in device mapping dialog

- Create new Map instance in handleDeviceSelect to trigger Svelte 5 reactivity
- Fixes issue where user selection wasn't updating the UI
- Ensures device mappings update correctly when user chooses from dropdown

packages/frontend/src/routes/play/components/device-mapping-dialog.svelte

@@ -73,7 +73,9 @@ function handleConfirm() {
 function handleDeviceSelect(recordedDeviceName: string, selectedDeviceId: string) {
 	const device = connectedDevices.find(d => d.id === selectedDeviceId);
 	if (device) {
-		mappings.set(recordedDeviceName, device);
+		const newMappings = new Map(mappings);
+		newMappings.set(recordedDeviceName, device);
+		mappings = newMappings;
 	}
 }