Use logger to add debug mode

When in debug mode,
- print the filename being saved in the `save_json` function
- print the filename being opened in `load_json` function.
- do whatever `verbose=True` does in the `search_object` function

When `load_database` or `save_database` fails, this would help troubleshoot the file that is causing the problem.

Start by reading the save_json, load_json, search_object, load_database, and save_database functions to understand the existing verbose behavior and failure paths. Add debug logging for filenames saved and opened, and make debug mode include the behavior provided by verbose=True in search_object; done means database failures expose the relevant filename.

Written by the indexing model from the issue text.