[FEATURE]: The documentation needs to include instructions for usage like opencode mcp add github --url https://api.githubcopilot.com/mcp --header "Authorization=Bearer {env:GITHUB_TOKEN}" #32259

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

• The documentation needs to include instructions for usage like opencode mcp add github --url https://api.githubcopilot.com/mcp --header "Authorization=Bearer {env:GITHUB_TOKEN}".
• Although support for this type of CLI syntax was added at feat(opencode): support non-interactive MCP add #31054 , there is no related documentation at https://opencode.ai/docs/zh-cn/cli/#mcp .