Make config files parsing more user friendly

Currently, the code does not give much information on why the parsing of config files fails.

We plan to improve that by giving more information on the exact location of the parsing error and give hints to the user on why it fails.

We could also add the option for the user to validate the parsed config files by printing the full parsed configuration in a tidy way and wait for user input before continuing with the processing.

Start by locating the config-file parsing entry point and tracing how parsing failures are currently reported. The issue describes adding the exact error location, hints about the cause, and an optional tidy configuration preview that waits for user input. Done means these user-facing improvements are available without changing the processing flow unexpectedly.

Written by the indexing model from the issue text.