Refactor: update README to enhance GitHub Copilot usage instructions …

[robpitcher]

This pull request updates the README.md to make the getting started instructions easier to follow and separates out the documentation of GitHub Copilot customizations into a dedicated appendix section. The changes clarify the workflow for testing Copilot customizations and provide better guidance for new users.

Improvements to onboarding and workflow clarity:

• Rewrote the "Getting Started" section as "Try it out", streamlining the instructions for testing GitHub Copilot customizations and running prompt templates for IaC creation.
• Added explicit steps for running the prompt template and deploying the generated IaC, making the process more approachable for first-time users.
• Enhanced the "Extras" section to encourage users to create their own prompts or delegate tasks to the Copilot Coding Agent, with clearer instructions for enabling and configuring the agent.

Documentation organization:

• Moved the table describing GitHub Copilot customizations to a new "Appendix" section, improving readability and separating reference material from the main workflow.
• Added a link from the main instructions to the appendix to help users discover how the repo guides Copilot.…and add appendix for customizations

[Copilot]

Pull request overview

This pull request refactors the README.md to improve the documentation structure and user experience for GitHub Copilot customizations. The changes move from a reference-first approach to a more action-oriented "Try it out" workflow, making it easier for new users to get started.

Changes:

• Renamed "Getting Started" to "Try it out" with streamlined step-by-step instructions for testing Copilot customizations
• Moved the GitHub Copilot customizations reference table to a new "Appendix" section
• Enhanced the "Extras" section with clearer guidance for creating custom prompts and using the GitHub Copilot Coding Agent

[Copilot]

Missing period at the end of this sentence. The instruction should end with a period for consistency with other numbered steps.

Suggested change

	2. Run the prompt template by typing `/demo-vm iacLanguage:bicep` or `/demo-vm iacLanguage:terraform` into GitHub Copilot Chat
	2. Run the prompt template by typing `/demo-vm iacLanguage:bicep` or `/demo-vm iacLanguage:terraform` into GitHub Copilot Chat.

[Copilot]

The formatting in this section is inconsistent. Line 25 presents a standalone suggestion ending with a period, while line 29 introduces a multi-step process with a colon. Consider restructuring for consistency, either by making both options follow the same format (both ending with colons leading to steps) or by making them parallel standalone statements.

Suggested change

	Try delegating IaC creation to GitHub Copilot Coding Agent:
	Try delegating IaC creation to GitHub Copilot Coding Agent.