raw output export

With the export framework, it would be trivial to implement an export writing the raw command output in a file, to be done either on end of task or on a key press.

I'll wait for a demand to implement it, though.

No files, tests, or entry points are named. Start by reading the export framework and existing exports, then trace where raw command output and task completion or key-press handling are exposed; done should include an agreed file destination and a confirmed trigger behavior.

Written by the indexing model from the issue text.