Support CLI Arguments for UI Client

[rholinshead]

When spawning the client from the CLI (or programatically in a process), it would be great to support specifying default/override values for transport, serverUrl and custom headers so that we can spin up the UI and connect to a server right away without having to manually set things in the UI to override local storage defaults.

I see the start script for the server does support serverUrl and transport but in the UI code the only supported overrides are via query params which are not defaulted from these values. There does not appear to be any way to default the headers right now.

An ideal flow would be something like:

npx @modelcontextprotocol/inspector --transport sse --server-url $SERVER_URL --header "Authorization: Bearer $SERVER_API_KEY"

which would spin up the UI and let me click connect right away