[BUG] [FEATURE REQUEST] - Add `claude mcp authenticate` option

Environment

• Platform (select one):
• [X] Anthropic API
• [X] AWS Bedrock
• [X] Google Vertex AI
• [X] Other: <!-- specify -->
• Claude CLI version: 1.0.83
• Operating System: RH9
• Terminal: Any (though this works a bit better in VSCode)

Bug Description

We have users connecting from their macs to a unix host where they run claude. We have OAuth MCPs they would like to connect to, but the OAuth creates a "localhost" and random port for the callback that is not forwarded from the unix host to the Mac where they would use a browser to authenticate

Steps to Reproduce

1. Create an OAuth MCP
2. Attempt to authenticate when connected to a remote host
3. laptop will get a 404 on the auth callback

Expected Behavior

Some way to authenticate the user to the MCP when running claude non-natively.

Actual Behavior

Unable to authenticate

Additional Context

Support for other OAuth authentication methods (e.g. Device Code) would be an acceptable alternative