release: run required live gates in standard workflow

[gaelic-ghost]

Problem

The documented standard release flow says it runs local live E2E and then promotes and healthchecks the LaunchAgent-backed service after publishing. scripts/repo-maintenance/release.sh currently runs neither action in run_standard_release.

During v11.2.0, those steps were completed manually after the GitHub release.

Acceptance criteria

• Standard mode runs validate-local-e2e.sh after the normal maintainer gate and before pushing the release branch.
• After merge, tag push, and GitHub release creation, standard mode runs SpeakSwiftlyServerTool launch-agent promote-live from synced main.
• The flow then runs the HTTP and MCP healthcheck and stops on failure.
• --skip-local-e2e and --skip-live-service-update work as documented.
• Release docs and script help stay aligned.
• Add focused script-level coverage or validation where practical.