Complete orchestration configuration

Use createOrchestratorWithFactory(config, { configureAgent, onChildOutcome?, descriptionExecution? }) when root/workers require complete authorized Agent/context settings before initialization. Return a complete plain configuration, resolve workers independently, and pass a ModelTask per operation for shared accounting. Read the recipe for precedence, reservations, async repair, cancellation/quarantine, source retention and cleanup. Existing createOrchestrator and synchronous callbacks retain their contracts.