feat(skills): add wellarchitected.github.com content to github-actions-dev

[aRustyDev]

Summary

Add references and patterns from https://wellarchitected.github.com to the github-actions-dev skill.

Rationale

The GitHub Well-Architected framework provides best practices for custom GitHub Action development that would complement the existing action development guidance.

Scope

• Add wellarchitected.github.com as a reference
• Incorporate framework patterns for action design
• Add guidance on action security, performance, and maintainability per the framework

Related Skills

This is part of a broader effort to add wellarchitected.github.com content to:

• cicd-github-actions-dev
• cicd-github-actions-ops
• github-actions-dev (this issue)
• github-app-dev
• iac-terraform-modules-eng
• iac-terraform-orchestration-ops