Improve the documentation for the elastic-agent inspect command

[vishaangelova]

Summary

This PR updates the elastic-agent inspect command reference to add more context, additional available options, and examples.

Resolves #3410

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

2. If you answered "Yes" to the previous question, please specify the tool(s) and model(s) used (e.g., Google Gemini, OpenAI ChatGPT-4, etc.).

Tool(s) and model(s) used: Cursor 2.2.36 with claude-4.5-opus-high model

[github-actions]

Vale Linting Results

Summary: 3 suggestions found

💡 Suggestions (3)

File	Line	Rule	Message
reference/fleet/agent-command-reference.md	461	Elastic.Wordiness	Consider using 'some' instead of 'some of the'.
reference/fleet/agent-command-reference.md	486	Elastic.WordChoice	Consider using 'deactivated, deselected, hidden, turned off, unavailable' instead of 'disabled', unless the term is in the UI.
reference/fleet/agent-command-reference.md	515	Elastic.WordChoice	Consider using 'can, might' instead of 'may', unless the term is in the UI.

[github-actions]

🔍 Preview links for changed docs

• reference/fleet/agent-command-reference.md

[blakerouse]

This looks good. Thanks for adding this.