Update repository README.md to reference current documentation

[hdamker]

Problem description

The repository README.md still points to three documents that have been moved to documentation/deprecated/:

• API_Release_Guidelines.md → replaced by documentation/release-process/
• API-Readiness-Checklist.md → replaced by documentation/readiness/api-readiness-checklist.md
• CHANGELOG_TEMPLATE.md → replaced by automated CHANGELOG generation

The SupportingDocuments/CHANGELOG_EXAMPLE.md reference is also outdated.

The current documentation structure is described in documentation/README.md but the repository README does not reference it.

Expected behavior

The "Release Process Information" section in README.md should point to the current documentation/README.md as the entry point, and remove or replace the references to the deprecated documents.

Alternative solution

None.

Additional context

The deprecated documents were moved in January 2026 as part of the release automation documentation restructuring. See documentation/deprecated/README.md for the deprecation mapping.