Document the release gate now that it exists

[DerekCorniello]

The README and the script header both said the release-level guarantee was planned rather than built, deliberately, so nobody would rely on a guarantee that was not enforced.

It is built now:

• Order strings properly, and run the examples at release mux-compiler#398 runs this script from verify-install in the release workflow, against the artifact it is about to publish, installed the way a user installs it. A broken example blocks the release.
• Run the published examples against the runtime under review mux-runtime#55 runs it on every pull request, because that repo has no release step.

So both places now say what actually happens. The ADR update is muxlang/mux-context#51.

[greptile-apps]

Greptile Summary

Updates documentation to reflect that example verification is now enforced by compiler release and runtime pull-request workflows.

• Documents the three callers of the shared example runner.
• Clarifies that compiler artifacts are tested as users install them before release.
• Updates the script header to match the current release-gate behavior.

Confidence Score: 5/5

The PR appears safe to merge because it only updates documentation to describe the now-active release gate.

The README and script-header changes are internally consistent, introduce no executable behavior changes, and reveal no actionable defects.

Important Files Changed

Filename	Overview
README.md	Replaces outdated planned-release-gate wording with a clear description of the three active verification paths.
scripts/run-examples.sh	Updates header comments to identify the current callers without changing executable behavior.

_{Reviews (1): Last reviewed commit: "Document the release gate now that it ex..." | Re-trigger Greptile}