Feat: Registry - Unauthenticated Access to the Anthropic Server list / Registry

Currently a user must be authenticated to retrieve the list of available / configured MCP servers registered with the gateway at `v0.1/servers`.
This returns the list of servers that the user has access to, unless they are an `admin` in which case the full list is returned.

With Github (and potentially others), the organisation can restrict end users to use a custom registry list, blocking them from using unapproved servers ([documentation](https://docs.github.com/en/copilot/how-tos/administer-copilot/manage-mcp-usage/configure-mcp-server-access)).

However this setup allows only a single URL e.g `https:my-internal-registry/v0.1/servers` with no authentication headers for it to work with IDE plugins - meaning with the current setup / configuration, both on nginx and the API, this endpoint cannot be used for MCP server discovery.

Could a flag be added that would allow the full list to be shown to users on a corporate network, bypassing the validation?
It could show the full list of servers and their configurations for the end user, however they would still be restricted in what they could interact with when their LLM agent attempts to reach out to the server with a client JWT