Build test

Spec §20.2 / §22.4: the "subjective critique-theater panel" is not enough on its own — a code-migration / tune-collab run must prove the build still passes. This atom shells out to the project's declared test commands and emits structured signals the devloop's until evaluator reads.

Inputs

• The active target stack (recorded in code/index.json + plan.md's targetStack block).
• The user's optional override (od plugin run --input testCommand='pnpm test').

Default commands by framework