Transform MCP server configurations to match Gemini CLI's expected format:
- Remove 'type' field (Gemini infers transport from field presence)
- Use 'httpUrl' field for HTTP streaming servers (type: "http")
- Keep 'url' field for SSE servers (type: "sse")
- Keep 'command' field for stdio servers unchanged
This fixes MCP servers not being recognized by Gemini CLI when
configured through cc-switch.