Adds copilot agents and skills

[jasonb5]

Description

• Technical document writer

• Testing specialist (focused coverage)

• Closes #<ISSUE_NUMBER_HERE>

Checklist

• My code follows the style guidelines of this project (black formatting)
• I have performed a self-review of my own code
• My changes generate no new warnings
• I have added tests that exercise my feature/fix and existing tests continue to pass
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding additions and changes to the documentation

[gold2718]

Fix typos?

Suggested change

	- Focus only on test files and avoid modifying production code unsless specifically requested
	Always include clear test descriptiuons and use appropriate testing patterns for python and pytest.
	- Focus only on test files and avoid modifying production code unless specifically requested
	Always include clear test descriptions and use appropriate testing patterns for python and pytest.

[rljacob]

Follow-on to #4940

[jedwards4b]

How do you invoke the various agents?

[jasonb5]

How do you invoke the various agents?

@jedwards4b If you're working in the copilot cli you can use the /agent command. In a PR you should be able to do @test-agent, and I believe it may also infer which agent to use based on the ask to @copilot e.g. @copilot write any missing tests for this pr.