Add MCP Server prompts and resources documentation

[michaellwest]

Scope

Document the 5 MCP prompts with parameters and workflow descriptions:

• find_items
• content_audit
• manage_security
• publish_content
• run_script_library

Document the spe://scripts/{path} resource for browsing the script library. Include usage examples showing how AI agents leverage prompts.

References

• SitecorePowerShell/mcp-server (Prompts/, Resources/ directories)

Files

• New mcp-server/prompts-and-resources.md
• SUMMARY.md — Add under MCP Server