Durable execution

import {
  createRuntime,
  createDurableRunner,
  createFileStepLog,
} from '@agentskit/runtime'

const runtime = createRuntime({ adapter, tools })
const durable = createDurableRunner({
  runtime,
  store: createFileStepLog({ path: '.agentskit/steps.jsonl' }),
})

await durable.run({ runId: 'r-42', input: 'refactor auth middleware' })
// Crash → restart → resume from last completed step
await durable.resume('r-42')

type StepRecord = {
  runId: string
  seq: number
  kind: 'llm' | 'tool' | 'event'
  at: number
  input: unknown
  output?: unknown
  error?: string
}