feat(tasks): OpenWorkflow-backed TaskEngine, task registry, outbox relay and op-ledger fencing (W1-4)

- TaskEngine port + OpenWorkflowEngine ([email protected].1, schema openworkflow):
  enqueue/signal/cancel/get/list/startWorker/stop
- defineTask registry with zod input schema; 9 stub task definitions (§3.1-8)
- TaskContext: step.run/sleep/waitForFact, redacting logger, traceId,
  attemptToken, abortSignal driven by PG cancel flag
- signal persists fact to tasks_fact first; waitForFact checks DB before waiting
- OutboxRelay: FOR UPDATE SKIP LOCKED, idempotencyKey outbox:<id>
- withAttemptToken fencing on tasks_op_ledger (own migration, merged in W2)
- tests: kill -9 crash recovery (child worker), cancel, idempotency,
  concurrent relays, early fact, lease-loss fencing

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/tasks/src/definitions.ts

@@ -0,0 +1,135 @@
+import { z } from "zod";
+import { defineTask, TaskRegistry } from "./registry";
+
+// 任务书 §3.1-8 的九类任务。W1 只落空壳:输入 schema + 回显 handler,W2 填充处理器。
+// 填充规则见 README「新增/填充任务」:副作用走 withAttemptToken,外部条件用 step.waitForFact,
+// 业务状态写业务表,不要放进 handler 返回值。
+
+const id = z.string().min(1);
+
+/** 空壳 handler:记录一条日志并回显输入 */
+function stub<I>(name: string) {
+  return async (ctx: { input: I; logger: { info(msg: string, f?: Record<string, unknown>): void } }) => {
+    // TODO(W2): 实现真实处理器
+    ctx.logger.info(`${name}: stub handler (TODO W2)`);
+    return { todo: true as const, task: name, input: ctx.input };
+  };
+}
+
+const NETWORK_RETRY = {
+  maximumAttempts: 5,
+  initialInterval: "1s",
+  backoffCoefficient: 2,
+  maximumInterval: "60s",
+} as const;
+const FILE_RETRY = {
+  maximumAttempts: 3,
+  initialInterval: "2s",
+  backoffCoefficient: 2,
+  maximumInterval: "60s",
+} as const;
+const DB_RETRY = { maximumAttempts: 3, initialInterval: "1s", backoffCoefficient: 2, maximumInterval: "30s" } as const;
+
+export const ingestFeed = defineTask({
+  name: "ingestFeed",
+  version: 1,
+  inputSchema: z.object({ feedSourceId: id }),
+  retryPolicy: NETWORK_RETRY,
+  handler: stub("ingestFeed"),
+});
+
+export const resolveObservation = defineTask({
+  name: "resolveObservation",
+  version: 1,
+  inputSchema: z.object({ observationId: id }),
+  retryPolicy: NETWORK_RETRY,
+  handler: stub("resolveObservation"),
+});
+
+export const evaluateAcquisition = defineTask({
+  name: "evaluateAcquisition",
+  version: 1,
+  inputSchema: z.object({
+    subscriptionId: id.optional(),
+    acquisitionSlotId: id.optional(),
+    sourceReleaseId: id.optional(),
+  }),
+  retryPolicy: DB_RETRY,
+  handler: stub("evaluateAcquisition"),
+});
+
+export const submitDownload = defineTask({
+  name: "submitDownload",
+  version: 1,
+  inputSchema: z.object({ acquisitionPlanId: id }),
+  retryPolicy: NETWORK_RETRY,
+  handler: stub("submitDownload"),
+});
+
+export const verifyAndImport = defineTask({
+  name: "verifyAndImport",
+  version: 1,
+  inputSchema: z.object({ downloadTaskId: id }),
+  retryPolicy: FILE_RETRY,
+  handler: stub("verifyAndImport"),
+});
+
+export const refreshMetadata = defineTask({
+  name: "refreshMetadata",
+  version: 1,
+  inputSchema: z.object({ mediaEntityId: id }),
+  retryPolicy: NETWORK_RETRY,
+  handler: stub("refreshMetadata"),
+});
+
+export const reconcileLibrary = defineTask({
+  name: "reconcileLibrary",
+  version: 1,
+  inputSchema: z.object({ libraryRootId: id.optional(), reconcileRunId: id.optional() }),
+  retryPolicy: FILE_RETRY,
+  handler: stub("reconcileLibrary"),
+});
+
+export const cleanupDownloadCache = defineTask({
+  name: "cleanupDownloadCache",
+  version: 1,
+  inputSchema: z.object({ downloaderInstanceId: id.optional() }),
+  retryPolicy: FILE_RETRY,
+  handler: stub("cleanupDownloadCache"),
+});
+
+export const resolveDecision = defineTask({
+  name: "resolveDecision",
+  version: 1,
+  inputSchema: z.object({ decisionId: id }),
+  retryPolicy: DB_RETRY,
+  handler: stub("resolveDecision"),
+});
+
+export const TASK_NAMES = [
+  "ingestFeed",
+  "resolveObservation",
+  "evaluateAcquisition",
+  "submitDownload",
+  "verifyAndImport",
+  "refreshMetadata",
+  "reconcileLibrary",
+  "cleanupDownloadCache",
+  "resolveDecision",
+] as const;
+export type TaskName = (typeof TASK_NAMES)[number];
+
+/** v0.1 的默认注册表;W2 把真实 handler 换进来(同名同版本替换,或升版本并保留旧版本) */
+export function createDefaultRegistry(): TaskRegistry {
+  return new TaskRegistry().register(
+    ingestFeed,
+    resolveObservation,
+    evaluateAcquisition,
+    submitDownload,
+    verifyAndImport,
+    refreshMetadata,
+    reconcileLibrary,
+    cleanupDownloadCache,
+    resolveDecision,
+  );
+}