client_name from CIMD should be used in device_name

[anyoung-tableau]

When an MCP client supports CIMD and provides its metadata document URL as its client_id to the /authorize endpoint, this document should contain a client_name.

For example, from https://vscode.dev/oauth/client-metadata.json:

{
  "client_name": "Visual Studio Code",
  "grant_types": [
    "authorization_code",
    "refresh_token",
    "urn:ietf:params:oauth:grant-type:device_code"
  ],
  "response_types": [
    "code"
  ],
  "token_endpoint_auth_method": "none",
  "application_type": "native",
  "client_id": "https://vscode.dev/oauth/client-metadata.json",
  "client_uri": "https://vscode.dev/product",
  "redirect_uris": [
    "http://127.0.0.1:33418/",
    "https://vscode.dev/redirect"
  ]
}

The value Visual Studio Code should be included in the value of the device_name provided to Tableau's OAuth auth endpoint so it appears in the user's accounts settings page Connected Clients list (instead of Unknown agent)

The changes necessary are in https://github.com/tableau/tableau-mcp/blob/main/src/server/oauth/authorize.ts