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/registry.ts

@@ -0,0 +1,77 @@
+import type { z } from "zod";
+import { UnknownTaskError } from "./errors";
+import type { RetryPolicy, TaskContext } from "./types";
+
+export interface TaskDefinition<S extends z.ZodType = z.ZodType, O = unknown> {
+  name: string;
+  /** 正整数;不兼容改动 +1,并在 worker 上同时注册新旧版本直到旧 run 清空 */
+  version: number;
+  inputSchema: S;
+  /** 步骤默认重试策略(步骤可单独覆盖)。外部网络类建议 5 次 1s→60s,文件类 3 次 */
+  retryPolicy?: Partial<RetryPolicy>;
+  handler: (ctx: TaskContext<z.output<S>>) => Promise<O>;
+}
+
+export function defineTask<S extends z.ZodType, O>(def: TaskDefinition<S, O>): TaskDefinition<S, O> {
+  if (!/^[A-Za-z][A-Za-z0-9_.-]*$/.test(def.name)) throw new Error(`invalid task name: ${def.name}`);
+  if (!Number.isInteger(def.version) || def.version < 1) throw new Error(`invalid task version: ${def.version}`);
+  return def;
+}
+
+export const engineVersion = (version: number) => `v${version}`;
+export const parseEngineVersion = (v: string | null): number | null => {
+  const m = v ? /^v(\d+)$/.exec(v) : null;
+  return m ? Number(m[1]) : null;
+};
+
+export class TaskRegistry {
+  private readonly defs = new Map<string, Map<number, TaskDefinition>>();
+
+  // biome-ignore lint/suspicious/noExplicitAny: 注册表按名存放异构的任务定义
+  register(...defs: TaskDefinition<any, any>[]): this {
+    for (const def of defs) {
+      let byVersion = this.defs.get(def.name);
+      if (!byVersion) {
+        byVersion = new Map();
+        this.defs.set(def.name, byVersion);
+      }
+      if (byVersion.has(def.version)) throw new Error(`task ${def.name}@${def.version} already registered`);
+      byVersion.set(def.version, def as TaskDefinition);
+    }
+    return this;
+  }
+
+  get(name: string, version: number): TaskDefinition {
+    const def = this.defs.get(name)?.get(version);
+    if (!def) throw new UnknownTaskError(name, version);
+    return def;
+  }
+
+  /** 新 run 一律用最高版本 */
+  latest(name: string): TaskDefinition {
+    const byVersion = this.defs.get(name);
+    if (!byVersion || byVersion.size === 0) throw new UnknownTaskError(name);
+    return byVersion.get(Math.max(...byVersion.keys()))!;
+  }
+
+  names(): string[] {
+    return [...this.defs.keys()].sort();
+  }
+
+  all(): TaskDefinition[] {
+    return [...this.defs.values()].flatMap((m) => [...m.values()]);
+  }
+
+  /** 按 StartWorkerOptions.versions 选择:"name@2" / "@1" / "name"(该任务全部版本) */
+  select(selectors?: string[]): TaskDefinition[] {
+    if (!selectors || selectors.length === 0) return this.all();
+    const picked = this.all().filter((d) =>
+      selectors.some((s) => {
+        const [name, ver] = s.split("@");
+        return (!name || name === d.name) && (ver === undefined || ver === "" || Number(ver) === d.version);
+      }),
+    );
+    if (picked.length === 0) throw new Error(`no task definitions match ${selectors.join(",")}`);
+    return picked;
+  }
+}