docs/superpowers/ held the working spec and plan, which pointed at the
local plan/ folder. The ARW6 module docs now cite the sections of
docs/arw6-compression.md, which gains the facts they relied on from the
spec: the NP field of word 0, the stream header word layout and how the
first half's residual lines are counted.
Co-Authored-By: Claude <noreply@anthropic.com>