/write-docs

Produce documentation that a stranger could use to operate, develop against, or contribute to the repo — grounded in source code, not vibes.

Mode selection (first thing you do)

if docs/CHANGELOG.md exists with a valid commit hash on line 1:
    BASE = that hash
    CHANGED = git diff --name-only $BASE..HEAD
    if CHANGED is empty:
        report "docs up to date at $BASE"; stop.
    else:
        run INCREMENTAL mode
else:
    run FULL mode

User can force full with "full draft", "from scratch", or by deleting docs/CHANGELOG.md.