Add GrokAdapter wrapping OpenAIAdapter with the official xAI base URL and
XAI_API_KEY. Wire provider 'grok' into createAdapter and extend AgentConfig /
OrchestratorConfig unions. Widen OpenAIAdapter.name to string so subclasses can
set their own provider label. Document usage in README and add example 12, a
runTeam() Express API demo using Grok.
Marcelo Ceccon