Module error 

Error types for ironflow operations.

This module defines two error enums:

• OperationError - top-level error returned by both shell and agent operations.
• AgentError - agent-specific error returned by AgentProvider::invoke.

AgentError converts into OperationError via the From trait, so agent errors propagate naturally through the ? operator.

Enums

AgentError

Error specific to agent (AI provider) invocations.

OperationError

Top-level error for any workflow operation (shell or agent).