Add metadata to snapshot

[bobbyhouse]

What I did

Because we are now marshaling data into Server and storing that data as Snapshot as part of a server's data in a profile or catalog. we need the complete object that was being returned by docker mcp catalog show which read from the file to get the metadata.

I have updated the Server struct to include Metadata so that we now get data like the following in profiles and catalogs

   "metadata": {
        "pulls": 500,
        "category": "finance",
        "tags": [
          "finance",
        ],
        "license": "MIT License",
        "owner": "owner-name"
      }

Testing Instructions

Verify that you see the metadata for the zerodha-kite MCP server that includes pulls and owner

docker mcp catalog-next create docker-mcp-catalog --from-legacy-catalog https://desktop.docker.com/mcp/catalog/v3/catalog.json
docker mcp profile create --name metadata
docker mcp profile server add metadata --catalog docker-mcp-catalog --catalog-server zerodha-kite
docker mcp profile show metadata --format json

Related issue

(not mandatory) A picture of a cute animal, if possible in relation to what you did