Redo Chronology I Smartguesser

The year smartguesser currently works, somehow, but seems clunky and hard to understand. In some cases years are interpreted as numbers, and other times as text. This algorithm should be reinterpreted and streamlined if possible

Locate the smartguesser implementation and any tests covering chronology or year parsing. Read how years are currently treated as numbers and text, then define consistent behavior and verify that the streamlined algorithm handles the existing cases without ambiguity.

Written by the indexing model from the issue text.