# Group Device Type Implementation

## Phase 1: Storage Layer
- [x] Add `group_device_ids`, `group_mode` fields to Device model
- [x] Add cycle detection + led_count resolution + group reference helpers to DeviceStore

## Phase 2: API Schemas
- [x] Add group fields to DeviceCreate, DeviceUpdate, DeviceResponse

## Phase 3: GroupLEDClient + Provider
- [x] Create `group_client.py` — GroupLEDClient (sequence slice / independent resample)
- [x] Create `group_provider.py` — GroupDeviceProvider
- [x] Register group provider in `led_client.py`

## Phase 4: Routes + Processing Pipeline
- [x] Update device routes — group-specific create/update logic, delete protection, cycle validation
- [x] Add group fields to DeviceInfo + _DEVICE_FIELD_DEFAULTS
- [x] Pass group context (device_store, group fields) to create_led_client

## Phase 5: Tests
- [x] Unit tests for cycle detection, led_count resolution, GroupLEDClient (20 tests, all passing)

## Phase 6: Frontend
- [x] Group device UI (child picker, mode selector, hide URL for groups)
- [x] i18n keys (en, ru, zh)
- [x] TypeScript types + API helper
- [x] Icon (layers) for group device type
- [x] CSS for group child rows