docs: clarify approval boundary

[xzlknr]

Summary

• Add a short approval-boundary checklist to the operator start guide
• Clarify which outputs are safe to prepare locally and which actions need explicit owner approval
• Keep the change scoped to operator-facing documentation

Closes #7

Testing

• npm run check passed
• npm run test:launch passed as part of npm test
• git diff --check passed

Note: full npm test currently reaches tests/regression.mjs, where the existing Windows test path fails with spawn npm ENOENT when the regression script tries to spawn npm run check. The direct npm run check command passes.