Function defineWorkflow

defineWorkflow(
    definition: AuthoringWorkflow,
): {
    description?: string;
    fields?: FieldEntry[];
    groups?: Group[];
    initialStage: string;
    lifecycle?: WorkflowLifecycle;
    name: string;
    predicates?: Record<string, string>;
    roleAliases?: RoleAliases;
    semantics?: Semantic[];
    stages: Stage[];
    start?: StartBlock;
    title: string;
}
Validate, desugar, and return a workflow definition in its stored shape. Throws with a formatted, path-prefixed error message if validation fails.

Example error:
```
defineWorkflow("article-review") failed validation (2 issues):
  - stages[1].transitions[0].to: transition target "ready" is not a declared stage. Known stages: "drafting", "review", "approved"
  - predicates.allActivitiesDone: predicate "allActivitiesDone" shadows the built-in $allActivitiesDone — pick another name
```
Parameters
- definition: AuthoringWorkflow
Returns {
    description?: string;
    fields?: FieldEntry[];
    groups?: Group[];
    initialStage: string;
    lifecycle?: WorkflowLifecycle;
    name: string;
    predicates?: Record<string, string>;
    roleAliases?: RoleAliases;
    semantics?: Semantic[];
    stages: Stage[];
    start?: StartBlock;
    title: string;
}