Update SUMMARY.md to reflect new documentation structure

- Restructured Developer MCP navigation with proper subsections
- Added Key Concepts subsection with Model Context Protocol and Context Engineering
- Added Host Setup subsection with guides for Claude Desktop, Claude Code, Cursor, and GitHub Copilot
- Removed old concepts.md file (replaced with concepts/README.md)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: Phil Whittaker

16/umbraco-cms/SUMMARY.md

@@ -359,7 +359,14 @@
 * [Webhooks](reference/webhooks/README.md)
   * [Expanding Webhook Events](reference/webhooks/expanding-webhook-events.md)
 * [Developer MCP](reference/developer-mcp/README.md)
-  * [Key Concepts](reference/developer-mcp//concepts.md)
+  * [Key Concepts](reference/developer-mcp/concepts/README.md)
+    * [Model Context Protocol](reference/developer-mcp/concepts/model-context-protocol.md)
+    * [Context Engineering](reference/developer-mcp/concepts/context-enginerring.md)
+  * [Host Setup](reference/developer-mcp/host-setup/README.md)
+    * [Claude Desktop](reference/developer-mcp/host-setup/claude-desktop.md)
+    * [Claude Code](reference/developer-mcp/host-setup/claude-code.md)
+    * [Cursor](reference/developer-mcp/host-setup/cursor.md)
+    * [GitHub Copilot](reference/developer-mcp/host-setup/github-copilot.md)
   * [Configuration](reference/developer-mcp//configuration.md)
   * [MCP as a Toolkit](reference/developer-mcp//mcp-toolkit.md)
   * [Making the most of the developer MCP](reference/developer-mcp/how-best-to-use.md)