FieldTypeDefinition interface exported

export interface FieldTypeDefinition {
  readonly type: FieldType;
  readonly category: FieldCategory;
  readonly description: string;
  /**
   * Key referencing a generator factory in the generator registry.
   * Types that share a generator use the same key with different params
   * (e.g. money, price, amount → "money" with different min/max).
   * If omitted, `generate()` falls back to a generic text generator.
   */
  readonly generator?: string;
  readonly params?: GeneratorParams;
}