The CLI (commands.cjs, init.cjs) uses `todos/completed/` but three
workflow files and three FEATURES.md docs referenced `todos/done/`.
This caused completed todos to land in different directories depending
on whether the CLI command or the workflow instructions were followed.
Closes#1438
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>