New MCP URL filtering needs wildcard support

Is your feature request related to a problem? Please describe. The MCP allowed_urls is not very useful: you need to specify exactly which URLs are allowed, so it would be better/just as much work to set the value in [[features.mcp.servers]].

Describe the solution you'd like allowed_urls should support wildcards in both the path and domain. This still allows admins to prevent SSRF, but also allows them to say "all the MCP servers at this location are fine".

Describe alternatives you've considered The main alternative would be to remove allowed_urls completely; as an admin if I already have to configure the URL, then I would rather fully setup the server than leave it up to an end user.