Patch edit

Spec §20.3 / §21.3.2: code-migration / tune-collab cannot ship a trustworthy diff when the agent rewrites whole files in one pass — the reviewer can't audit the change. This atom enforces "one step per turn, smallest possible localised edit".

Inputs

• plan/steps.json from rewrite-plan.
• The current value of iterations (the daemon's per-stage counter).
• code/index.json for the file's known imports + neighbours.

Output

The atom mutates files inside the project cwd via the file-edit tool. After every iteration, it writes a per-step receipt: