Connect Copilot's local validation to CI evidence.

Generate Copilot instructions

init writes .github/copilot-instructions.md. The instruction asks Copilot to use DiffCI before PR-ready work, inspect fallback reasons, and keep the repository's normal validation authoritative.

The local check command can execute inferred full and selected test commands. Use observe --no-send for analysis without repository-script execution.

Add the observer job separately

npx "@diffci.com/diffci@latest" init --workflow
npx "@diffci.com/diffci@latest" verify-workflow

The generated Action job is observation-only. It should use continue-on-error, remain outside other jobs' needs graphs, and never become a required-check dependency. This is a different safety boundary from the local check command.

Keep the two evidence sources distinct

Copilot's local run answers what the checked-out change reaches and, when possible, measures paired commands. The Action produces a report artifact inside GitHub Actions without changing what other jobs execute. Neither result is permission to omit required CI.

Verify the Copilot and Actions setup

• Confirm .github/copilot-instructions.md contains the repository policy and that generated workflow changes remain separately reviewable.
• Run verify-workflow and confirm the observer uses continue-on-error and is not required by another job.
• Check that the observation artifact is produced while the repository's existing required jobs still execute unchanged.