Maintenance: Retire stale process documentation and automation #5636

Summary

The process documentation in docs/roadmap.md, docs/maintainers.md, and docs/contributing/* was removed from the MkDocs navigation in #5426 but remained published and reachable. These orphaned pages have since become stale and diverged from the repository's current processes.

Why is this needed?

The pages present the 2025 roadmap as current, contain broken links and removed commands such as make dev and npm run test:parallel, and make inaccurate claims about coverage enforcement and PR title-check comments. They also duplicate guidance now maintained in CONTRIBUTING.md and CODING_STANDARDS.md.

The maintainer documentation additionally describes repository-level label and release automation that has moved to the organization level. Keeping both versions published makes it unclear which instructions are authoritative.

Which area does this relate to?

• Automation
• Governance

Solution

Retire the orphaned process pages and consolidate current maintainer and contributor guidance in the root MAINTAINERS.md and CONTRIBUTING.md. Correct stale commands, links, and process claims, and remove the obsolete stale-issues and post-release repository workflows and supporting script now superseded by organization-level automation.

Acknowledgment

• This request meets Powertools for AWS Lambda (TypeScript) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Python, Java, and .NET

Disclaimer: After creating an issue, please wait until it is triaged and confirmed by a maintainer before implementing it. This will reduce amount of rework and the chance that a pull request gets rejected.

Future readers

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