fix: remove id property from Server schema (#339)

The Server schema should not have its own `id` property as the ID is
managed by the registry system through the
`_meta["io.modelcontextprotocol.registry"].id` field.

Fixes #336

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

Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>
Co-authored-by: adam jones <domdomegg@users.noreply.github.com>

docs/server-registry-api/openapi.yaml

@@ -203,10 +203,6 @@ components:
         - description
         - version_detail
       properties:
-        id:
-          type: string
-          format: uuid
-          example: "123e4567-e89b-12d3-a456-426614174000"
         name:
           type: string
           description: "Reverse DNS name of the MCP server"