Update copilot starter skill

[tagedeep]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, agent, skill, or workflow file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, skill, or workflow with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.

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Description

This pull request updates an existing Copilot skill to align it with the current structure of the github/awesome-copilot repository.

The changes are intentionally minimal and focused on fixing outdated references and output guidance:

• replaces outdated chat mode references with agents
• removes old collections guidance
• removes old prompt-folder assumptions and points to skills instead
• updates repository resource references to match the current repo structure
• updates workflow guidance so copilot-setup-steps.md is treated as the authored source and copilot-setup-steps.lock.yml as the compiled artifact
• fixes an outdated internal instructions reference
• tightens checklist language around frontmatter and metadata requirements

The purpose of this change is to keep the skill useful without rewriting it more than necessary.

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Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• New agentic workflow.
• Update to existing instruction, prompt, agent, plugin, skill, or workflow.
• Other (please specify):

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Additional Notes

This update does not introduce a new contribution type. It only revises an existing skill so that it reflects the current awesome-copilot repository conventions.

The change explicitly ignores plugins for this guide, as they are out of scope.

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.