Omitted fields on set_task_config/set_list_config used to be indistinguishable
from an explicit clear, so any single-field update silently wiped every other
override (including SessionSkills, which wasn't even a tool parameter). Now
only the fields you pass are changed; clearing an override requires naming it
in the new clearFields array (a sentinel string doesn't work uniformly since
maxTurns is an int). set_list_config's "all four null deletes the config" case
is preserved but only reachable via clearFields. Return values now reflect the
full resulting config.
mika kuns
5eea439129