Add a withLogged utility method

As I wrap async throwing work in logs, I usually end up with a utility like this in every project:

```swift
func withLogged(
operation: String,
level: Logger.Level = .info,
_ work: () async throws -> Return
) async throws -> Return {
let logger = Logger.current
logger.log(level: level, "\(operation) starting")
do {
let result = try await work()
logger.log(level: level, "\(operation) finished successfully")
return result
} catch {
logger.log(level: level, "\(operation) failed", error: error)
throw error
}
}
```

Would it make sense to upstream here?

Start by reviewing swift-log's existing Logger APIs and repository conventions, then assess where the proposed withLogged utility would belong. Done means the API and logging behavior are agreed for upstream inclusion and verified against the repository's relevant tests.

Written by the indexing model from the issue text.