* setup golden toolkit
* implemented `GoldenTestApplicationMock`
* added devices with dark theme
* implemented MeteringScreen golden test
* moved platform channel logic to app mock
* implemented SettingsScreen golden test
* gitignore golden tests failures
* Create dart_test.yaml
* adjusted `RulerSlider` ticks height
* set master screenshots
* run golden tests on ci
* fixed `LightSensorService` tests
* removed golden workflow call from PR check
* Update pr_check.yml
- Fixed test coverage calculation
- Removed `mockito` from the application mock
- Implemented platform channel mocks to mimic incident light metering
- Covered providers with unit tests
- Covered metering screen pickers with widget tests
- Laid foundation for integration tests