Improve error messages in config

**Problem**
When working with types, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Start by locating the configuration parsing and type-validation entry points in the repository, then reproduce the current errors for the reported type-related cases. Done means the error messages provide more descriptive debugging context and the relevant behavior is covered by tests, if existing tests are found.

Written by the indexing model from the issue text.