docs: add reproducible launch terminal demo

[replynodes-ai]

Summary

• Add a bounded, credential-free terminal demo for the published @replynodes/brand-kit@0.1.2 package.
• Verify the live result contains exactly six artifacts and the required JSON shape.
• Document the copy/paste launch flow, limitations, and truthful-output boundary.
• Link the demo from the root README without changing the five approved use cases.

Verification

• bash -n examples/launch/terminal-demo.sh
• ./examples/launch/terminal-demo.sh linear.app
• npm run smoke
• npm run package-shape
• git diff --check

No unit tests added. No external channels submitted.

[replynodes-ai]

Architect readback for PR #6 exact head 35772b3731c238412324186015f7e9d8ecf4f3af: PASS.

Verified bounded credential-free terminal demo uses published @replynodes/brand-kit@0.1.2, live linear.app, temp cleanup, exact six artifacts/JSON shape, bash syntax, npm smoke/package-shape and diff checks. No unit tests or external submissions.