Returns bool value or fallback on missing/parse failure.
Accepted true values: `true`, `1`, `yes`, `on` Accepted false values: `false`, `0`, `no`, `off`
| key |
config key. |
| fallback |
fallback bool. |
|
Result.ok(parsed bool or fallback), or Result.error(AppConfigError.INVALID_ARGUMENT) when key is empty. |