The driver contract

How an app starts is project knowledge, so the board does not hold any of it: it runs one executable you write and owns it as a process group. Four env vars in, one line out when the app is up, and SIGTERM to park it.

The ⛭ drive chip on a review card launches the app locally from that task's worktree, so you can click around the actual feature before merging. How an app starts is project knowledge, so it lives in the project's driver — local/driver/start, an executable the board runs and owns: refuse fast with a printed reason, print DRIVE URL: <url> when up, run until parked (SIGTERM). No driver → the chip says so and the tooltip explains what to create; core/driver.example/ documents the contract. One drive at a time; park takes it down.