Agents

Removed in operonx 1.16. The old operonx.agents module is gone. Agents live in the operonx-agents package, imported as operonx.agents (an alias of operonx_agents): Agent, Runner, tools, approvals, sessions, MCP, agent_service, evals. Start at operonx_agents/guide/01-agents.md; MIGRATION.md maps each old name to its replacement.