- Updated `shelly` class to support POST request handling (`sendPostRequest`) and server URL validation.
- Adjusted `shelly_device_state` to handle object-based `status` and `settings`, adding a `populate` method for data initialization.
- Added `shelly_device_switch` helper to manage switching operations via Shelly API.
- Removed unused `api_url` property in `shelly` class.
- Modified `shelly_i` interface with definitions for `requireValidServerUrl` and `sendPostRequest`.