Implement aborting search early using a key input

The user should be notified if a search result is found and should be able to stop the search. The results found until then should be collected and returned as a json array as usual

Start at the CLI search entry point and trace how results are collected and serialized. Determine how key input can notify the user when a result is found and stop the search while preserving results collected so far. Done means an interrupted search returns the collected results as the usual JSON array.

Written by the indexing model from the issue text.