Adhere to user callback error spec

Have a look at the parent project and/or develop docs.

We should be already wrapping most cases; there might be improvements necessary when it comes to emitting client reports.

Start by reading the parent project and the develop docs referenced in the issue, then compare the SDK's current user-callback wrapping and client-report behavior with that specification. Done means the remaining callback cases are handled as required and client reports are emitted consistently; the issue does not name files or tests to run.

Vom Indexierungsmodell aus dem Issue-Text verfasst.