fix: :bug: Add requestOptions to YAML config for mcp

[chezsmithy]

Description

Add request options to mcp server YAML config. Without this in place you can't pass headers for example.

Checklist

• [X] I've read the contributing guide
• [X] The relevant docs, if any, have been updated or created
• [X] The relevant tests, if any, have been updated or created

Screenshots

[ For visual changes, include screenshots. Screen recordings are particularly helpful, and appreciated! ]

Tests

Confirmed the following configuration loads headers in:

https://github.com/chezsmithy/continue/blob/16ef20aeca9696f0b751e590671111eafc5fcda7/core/context/mcp/MCPConnection.ts#L352

name: SSE Server
version: 0.0.1
schema: v1
mcpServers:
  - name: sse-server
    type: sse
    url: https://www.example.com
    requestOptions:
      headers: { Authorization: "Bearer ABC", JWT: XXASDASDSAS }