docs(mcp): add opencode-specific config example
Problem
The MCP setup docs at docs/source/remote/access/mcp.md only show the Claude Code/Desktop config format (command as string + separate args array). opencode uses a different schema that requires "type": "local" and places command and arguments in a single array.
Users following the current docs for opencode get ConfigInvalidError because of three schema mismatches:
- Missing required
"type": "local"— opencode'sMcpLocalConfigschema has"required": ["type", "command"] commandmust be an array, not a string — opencode expects["npx", "mcp-remote", "..."]- No
argsfield exists in opencode's schema — both local and remote config types have"additionalProperties": false
Reported by @thiagocsf in gitlab-org#21994 (comment 3342544059)
Solution
Add an opencode-specific config example alongside the existing Claude snippet, with a note explaining the differences.
The existing Claude Code/Cursor/Codex snippet is unchanged.