generated from coulomb/repo-seed
edit()/overlay()/apply_overlay() on InformationSpace. edit() unifies the write path through one principled route — draft overlay then apply: write-through-capable target fast-forwards (APPLIED), read-only target keeps the draft as local truth (KEPT_DRAFT), external drift refuses (no clobber). Integration tests cover all four. 64 tests green, pyflakes clean. Flips WP-0008 done. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>