feat: Support fal MCP Server

Summary

I tried to add the fal.ai MCP server, but was unable to as it assumed it needed OAuth.

See: https://fal.ai/docs/documentation/setting-up/mcp#other-mcp-clients

Edit: See additional info but was Abel to setup using the add json but could be improved DX by allowing the add and for it not to think it needs OAuth when this MCP server does not.

Expected Behavior

A setup and configured MCP server for fal.ai.

Also adding the header option is nice so can set the auth header in the add. Perhaps this is possible with add-json, but that's not very terminal friendly to do.

Actual Behavior

Does not setup MCP server.

Steps to reproduce the issue

first tried:

cmd mcp add --transport http fal-ai \
  https://mcp.fal.ai/mcp \
  --header "Authorization: Bearer <my-api-key>

but that asked for OAuth and did https://auth.fal.ai/authorize?response_type=code&client_id=command-code&redirect_uri=XXXX&code_challenge=4B2giHGR8eGid708raKhuVhFheiSVwjjzuDZa8Sa4Ak&code_challenge_method=S256&scope=openid+profile+email+offline_access which fal did not know how to handle

2. Then tried just

 cmd mcp add --transport http fal-ai https://mcp.fal.ai/mcp

and same.

Command Code Version

0.37.2

Operating System

macOS

Terminal/IDE

ghostty

Shell

zsh

Additional context

I got the MCP serve setup and working using:

cmd mcp add-json fal-ai '{"type":"http","url":"https://mcp.fal.ai/mcp","headers":{"Authorization":"Bearer my-api-token"}}'

cmd mcp add のエントリポイントから始め、その動作を cmd mcp add-json と比較します。issue に記載されているコマンドを使って fal.ai HTTP サーバーのセットアップを再現します。add が示された Authorization ヘッダーを受け入れ、このサーバーに対して OAuth を開始せず、動作している add-json の設定を維持できれば完了です。