feat(M01-C): 建立MySQL异步任务基础

backend/package.json

@@ -11,12 +11,13 @@
     "dev": "tsx watch src/server.ts",
     "build": "tsc -p tsconfig.json",
     "start": "node dist/server.js",
+    "start:worker": "node dist/tasks/worker.js",
     "db:migrate:plan": "npm run build && node dist/db/migrate-cli.js plan",
     "db:migrate:up": "npm run build && node dist/db/migrate-cli.js up",
     "db:migrate:verify": "npm run build && node dist/db/migrate-cli.js verify",
     "db:migrate:down": "npm run build && node dist/db/migrate-cli.js down",
     "test:mysql:migration": "npm run build && node tests/mysql-migration-roundtrip.test.mjs",
-    "test": "npm run build && node tests/backend-contract.test.mjs && node tests/migration-contract.test.mjs && node tests/mysql-pool-contract.test.mjs && node tests/migration-runner.test.mjs && node tests/legacy-money.test.mjs && node tests/legacy-read-repository.test.mjs"
+    "test": "npm run build && node tests/backend-contract.test.mjs && node tests/migration-contract.test.mjs && node tests/mysql-pool-contract.test.mjs && node tests/migration-runner.test.mjs && node tests/legacy-money.test.mjs && node tests/legacy-read-repository.test.mjs && node tests/task-repository.test.mjs"
   },
   "dependencies": {
     "@fastify/cors": "^11.2.0",

backend/src/db/migration-runner.ts

@@ -19,10 +19,19 @@ export interface MigrationExecutionResult extends MigrationPlan {
 }
 
 const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), '../../..');
-const migrationFiles: Record<MigrationDirection, string> = {
-  up: 'database/migrations/2026061601_m01b_core_schema.up.sql',
-  verify: 'database/migrations/2026061601_m01b_core_schema.verify.sql',
-  down: 'database/migrations/2026061601_m01b_core_schema.down.sql'
+const migrationFiles: Record<MigrationDirection, readonly string[]> = {
+  up: [
+    'database/migrations/2026061601_m01b_core_schema.up.sql',
+    'database/migrations/2026061802_m01c_async_tasks.up.sql'
+  ],
+  verify: [
+    'database/migrations/2026061601_m01b_core_schema.verify.sql',
+    'database/migrations/2026061802_m01c_async_tasks.verify.sql'
+  ],
+  down: [
+    'database/migrations/2026061802_m01c_async_tasks.down.sql',
+    'database/migrations/2026061601_m01b_core_schema.down.sql'
+  ]
 };
 
 export function splitSqlStatements(sql: string): string[] {
@@ -110,12 +119,15 @@ export function splitSqlStatements(sql: string): string[] {
 }
 
 export async function loadMigrationPlan(direction: MigrationDirection): Promise<MigrationPlan> {
-  const relativeFile = migrationFiles[direction];
-  const sql = await readFile(resolve(repoRoot, relativeFile), 'utf8');
+  const relativeFiles = migrationFiles[direction];
+  const sqlParts = await Promise.all(
+    relativeFiles.map((relativeFile) => readFile(resolve(repoRoot, relativeFile), 'utf8'))
+  );
+  const sql = sqlParts.join('\n');
 
   return {
     direction,
-    file: relativeFile,
+    file: relativeFiles.join(','),
     checksum: createHash('sha256').update(sql).digest('hex'),
     statements: splitSqlStatements(sql)
   };
@@ -134,7 +146,7 @@ export async function executeMigrationPlan(
   for (const [index, statement] of plan.statements.entries()) {
     const [result] = await pool.query(statement);
     if (plan.direction === 'verify') {
-      const minimumRows = [10, 26, 1][index] ?? 1;
+      const minimumRows = [10, 26, 1, 2, 5, 1][index] ?? 1;
       if (!Array.isArray(result) || result.length < minimumRows) {
         throw new Error(
           `Migration verification statement ${index + 1} returned fewer than ${minimumRows} rows.`

backend/src/tasks/outbox-repository.ts

@@ -0,0 +1,69 @@
+import type { ResultSetHeader, RowDataPacket } from 'mysql2/promise';
+import type { MySqlPool } from '../db/mysql.js';
+
+export interface AppendOutboxEventInput {
+  tenantId: string;
+  aggregateType: string;
+  aggregateId: string;
+  eventType: string;
+  idempotencyKey: string;
+  payload: unknown;
+  availableAt?: Date;
+}
+
+type SqlExecutor = Pick<MySqlPool, 'execute'>;
+
+export class OutboxRepository {
+  constructor(private readonly executor: SqlExecutor) {}
+
+  async append(input: AppendOutboxEventInput): Promise<{ id: string; created: boolean }> {
+    const [result] = await this.executor.execute<ResultSetHeader>(
+      `INSERT IGNORE INTO qipai_outbox_events
+        (tenant_id, aggregate_type, aggregate_id, event_type,
+         idempotency_key, payload, available_at)
+       VALUES (?, ?, ?, ?, ?, CAST(? AS JSON), ?)`,
+      [
+        input.tenantId,
+        input.aggregateType,
+        input.aggregateId,
+        input.eventType,
+        input.idempotencyKey,
+        JSON.stringify(input.payload),
+        input.availableAt ?? new Date()
+      ]
+    );
+    if (result.insertId > 0) {
+      return { id: String(result.insertId), created: true };
+    }
+    const [rows] = await this.executor.execute<Array<RowDataPacket & { id: string }>>(
+      `SELECT id FROM qipai_outbox_events
+       WHERE tenant_id = ? AND idempotency_key = ?`,
+      [input.tenantId, input.idempotencyKey]
+    );
+    if (!rows[0]) throw new Error('Idempotent outbox lookup failed after duplicate insert.');
+    return { id: String(rows[0].id), created: false };
+  }
+
+  async markPublished(eventId: string): Promise<boolean> {
+    const [result] = await this.executor.execute<ResultSetHeader>(
+      `UPDATE qipai_outbox_events
+       SET status = 'PUBLISHED', published_at = UTC_TIMESTAMP(3),
+           attempts = attempts + 1, last_error = NULL
+       WHERE id = ? AND status = 'PENDING'`,
+      [eventId]
+    );
+    return result.affectedRows === 1;
+  }
+
+  async markFailed(eventId: string, error: unknown, delayMs: number): Promise<boolean> {
+    const message = error instanceof Error ? error.message : String(error);
+    const [result] = await this.executor.execute<ResultSetHeader>(
+      `UPDATE qipai_outbox_events
+       SET available_at = DATE_ADD(UTC_TIMESTAMP(3), INTERVAL ? MICROSECOND),
+           attempts = attempts + 1, last_error = ?
+       WHERE id = ? AND status = 'PENDING'`,
+      [delayMs * 1000, message.slice(0, 1000), eventId]
+    );
+    return result.affectedRows === 1;
+  }
+}

backend/src/tasks/task-repository.ts

@@ -0,0 +1,177 @@
+import type { PoolConnection, ResultSetHeader, RowDataPacket } from 'mysql2/promise';
+import type { MySqlPool } from '../db/mysql.js';
+
+export const taskTypes = [
+  'notification.dispatch',
+  'order.advance',
+  'device.command',
+  'refund.query',
+  'statistics.aggregate',
+  'outbox.publish'
+] as const;
+
+export type TaskType = (typeof taskTypes)[number];
+export type TaskStatus =
+  | 'PENDING'
+  | 'RUNNING'
+  | 'RETRY'
+  | 'SUCCEEDED'
+  | 'FAILED'
+  | 'COMPENSATION_REQUIRED'
+  | 'CANCELLED';
+
+export interface AsyncTask {
+  id: string;
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: unknown;
+  status: TaskStatus;
+  attempts: number;
+  maxAttempts: number;
+}
+
+interface TaskRow extends RowDataPacket {
+  id: string;
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: string | object;
+  status: TaskStatus;
+  attempts: number;
+  maxAttempts: number;
+}
+
+export interface EnqueueTaskInput {
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: unknown;
+  priority?: number;
+  availableAt?: Date;
+  maxAttempts?: number;
+}
+
+export class TaskRepository {
+  constructor(private readonly pool: MySqlPool) {}
+
+  async enqueue(input: EnqueueTaskInput): Promise<{ id: string; created: boolean }> {
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `INSERT IGNORE INTO qipai_async_tasks
+        (tenant_id, task_type, idempotency_key, payload, priority, available_at, max_attempts)
+       VALUES (?, ?, ?, CAST(? AS JSON), ?, ?, ?)`,
+      [
+        input.tenantId,
+        input.taskType,
+        input.idempotencyKey,
+        JSON.stringify(input.payload),
+        input.priority ?? 0,
+        input.availableAt ?? new Date(),
+        input.maxAttempts ?? 8
+      ]
+    );
+    if (result.insertId > 0) {
+      return { id: String(result.insertId), created: true };
+    }
+    const [rows] = await this.pool.execute<Array<RowDataPacket & { id: string }>>(
+      `SELECT id FROM qipai_async_tasks
+       WHERE tenant_id = ? AND task_type = ? AND idempotency_key = ?`,
+      [input.tenantId, input.taskType, input.idempotencyKey]
+    );
+    if (!rows[0]) throw new Error('Idempotent task lookup failed after duplicate insert.');
+    return { id: String(rows[0].id), created: false };
+  }
+
+  async claimNext(workerId: string, leaseMs: number): Promise<AsyncTask | null> {
+    const connection = await this.pool.getConnection();
+    try {
+      await connection.beginTransaction();
+      await this.recoverExpiredLease(connection);
+      const [rows] = await connection.execute<TaskRow[]>(
+        `SELECT id, tenant_id AS tenantId, task_type AS taskType,
+                idempotency_key AS idempotencyKey, payload, status,
+                attempts, max_attempts AS maxAttempts
+         FROM qipai_async_tasks
+         WHERE status IN ('PENDING', 'RETRY')
+           AND available_at <= UTC_TIMESTAMP(3)
+         ORDER BY priority DESC, available_at ASC, id ASC
+         LIMIT 1
+         FOR UPDATE SKIP LOCKED`
+      );
+      const row = rows[0];
+      if (!row) {
+        await connection.commit();
+        return null;
+      }
+
+      await connection.execute(
+        `UPDATE qipai_async_tasks
+         SET status = 'RUNNING',
+             lease_owner = ?,
+             lease_expires_at = DATE_ADD(UTC_TIMESTAMP(3), INTERVAL ? MICROSECOND),
+             attempts = attempts + 1,
+             last_error = NULL
+         WHERE id = ?`,
+        [workerId, leaseMs * 1000, row.id]
+      );
+      await connection.commit();
+      return {
+        ...row,
+        id: String(row.id),
+        tenantId: String(row.tenantId),
+        status: 'RUNNING',
+        attempts: row.attempts + 1,
+        payload: typeof row.payload === 'string' ? JSON.parse(row.payload) : row.payload
+      };
+    } catch (error) {
+      await connection.rollback();
+      throw error;
+    } finally {
+      connection.release();
+    }
+  }
+
+  async complete(taskId: string, workerId: string): Promise<boolean> {
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `UPDATE qipai_async_tasks
+       SET status = 'SUCCEEDED', completed_at = UTC_TIMESTAMP(3),
+           lease_owner = NULL, lease_expires_at = NULL
+       WHERE id = ? AND status = 'RUNNING' AND lease_owner = ?`,
+      [taskId, workerId]
+    );
+    return result.affectedRows === 1;
+  }
+
+  async fail(task: AsyncTask, workerId: string, error: unknown): Promise<TaskStatus> {
+    const terminal = task.attempts >= task.maxAttempts;
+    const nextStatus: TaskStatus = terminal ? 'COMPENSATION_REQUIRED' : 'RETRY';
+    const delayMs = retryDelayMs(task.attempts);
+    const message = error instanceof Error ? error.message : String(error);
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `UPDATE qipai_async_tasks
+       SET status = ?, available_at = DATE_ADD(UTC_TIMESTAMP(3), INTERVAL ? MICROSECOND),
+           lease_owner = NULL, lease_expires_at = NULL, last_error = ?
+       WHERE id = ? AND status = 'RUNNING' AND lease_owner = ?`,
+      [nextStatus, delayMs * 1000, message.slice(0, 1000), task.id, workerId]
+    );
+    if (result.affectedRows !== 1) {
+      throw new Error(`Task ${task.id} lease was lost before failure could be recorded.`);
+    }
+    return nextStatus;
+  }
+
+  private async recoverExpiredLease(connection: PoolConnection): Promise<void> {
+    await connection.execute(
+      `UPDATE qipai_async_tasks
+       SET status = 'RETRY', lease_owner = NULL, lease_expires_at = NULL,
+           available_at = UTC_TIMESTAMP(3),
+           last_error = COALESCE(last_error, 'worker lease expired')
+       WHERE status = 'RUNNING' AND lease_expires_at < UTC_TIMESTAMP(3)`
+    );
+  }
+}
+
+export function retryDelayMs(attempts: number): number {
+  const exponent = Math.max(0, Math.min(attempts - 1, 20));
+  return Math.min(60 * 60 * 1000, 1000 * 2 ** exponent);
+}

backend/src/tasks/worker.ts

@@ -0,0 +1,76 @@
+import { hostname } from 'node:os';
+import { randomUUID } from 'node:crypto';
+import { resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import type { AsyncTask, TaskType } from './task-repository.js';
+import { TaskRepository } from './task-repository.js';
+import { closeMySqlPool, createMySqlPool } from '../db/mysql.js';
+import { loadConfig } from '../config.js';
+
+type TaskHandler = (task: AsyncTask) => Promise<void>;
+
+export interface WorkerOptions {
+  repository: TaskRepository;
+  handlers: ReadonlyMap<TaskType, TaskHandler>;
+  workerId: string;
+  leaseMs?: number;
+}
+
+export class TaskWorker {
+  private stopping = false;
+
+  constructor(private readonly options: WorkerOptions) {}
+
+  stop(): void {
+    this.stopping = true;
+  }
+
+  async runOnce(): Promise<boolean> {
+    const task = await this.options.repository.claimNext(
+      this.options.workerId,
+      this.options.leaseMs ?? 60_000
+    );
+    if (!task) return false;
+
+    const handler = this.options.handlers.get(task.taskType);
+    try {
+      if (!handler) throw new Error(`No handler registered for task type ${task.taskType}.`);
+      await handler(task);
+      if (!(await this.options.repository.complete(task.id, this.options.workerId))) {
+        throw new Error(`Task ${task.id} lease was lost before completion.`);
+      }
+    } catch (error) {
+      await this.options.repository.fail(task, this.options.workerId, error);
+    }
+    return true;
+  }
+
+  async run(pollIntervalMs = 1000): Promise<void> {
+    while (!this.stopping) {
+      const processed = await this.runOnce();
+      if (!processed) await sleep(pollIntervalMs);
+    }
+  }
+}
+
+export function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+if (process.argv[1] && fileURLToPath(import.meta.url) === resolve(process.argv[1])) {
+  const config = loadConfig();
+  const pool = createMySqlPool(config);
+  const worker = new TaskWorker({
+    repository: new TaskRepository(pool),
+    handlers: new Map(),
+    workerId: `${hostname()}:${process.pid}:${randomUUID()}`
+  });
+  const shutdown = () => worker.stop();
+  process.on('SIGINT', shutdown);
+  process.on('SIGTERM', shutdown);
+  try {
+    await worker.run();
+  } finally {
+    await closeMySqlPool(pool);
+  }
+}

backend/tests/migration-contract.test.mjs

@@ -12,6 +12,9 @@ const downSql = read('database/migrations/2026061601_m01b_core_schema.down.sql')
 const verifySql = read('database/migrations/2026061601_m01b_core_schema.verify.sql');
 const seedSql = read('database/seeds/2026061601_m01b_minimal_seed.sql');
 const legacyFixtureSql = read('database/fixtures/2026061801_m01b_legacy_schema.sql');
+const asyncUpSql = read('database/migrations/2026061802_m01c_async_tasks.up.sql');
+const asyncDownSql = read('database/migrations/2026061802_m01c_async_tasks.down.sql');
+const asyncVerifySql = read('database/migrations/2026061802_m01c_async_tasks.verify.sql');
 
 const coreTables = [
   'qipai_schema_migrations',
@@ -73,4 +76,14 @@ assert.match(legacyFixtureSql, /DECIMAL\(10,\s*2\)/);
 assert.match(legacyFixtureSql, /LEGACY-SANITIZED-001/);
 assert.doesNotMatch(legacyFixtureSql, /(?:https?:\/\/|@|password|secret|token)/i);
 
-console.log('PASS: M01-B migration contract is present.');
+for (const table of ['qipai_outbox_events', 'qipai_async_tasks']) {
+  assert.match(asyncUpSql, new RegExp(`CREATE TABLE IF NOT EXISTS ${table}\\b`));
+  assert.match(asyncDownSql, new RegExp(`DROP TABLE IF EXISTS ${table}\\b`));
+  assert.match(asyncVerifySql, new RegExp(`'${table}'`));
+}
+assert.match(asyncUpSql, /UNIQUE KEY uq_qipai_outbox_events_idempotency/);
+assert.match(asyncUpSql, /UNIQUE KEY uq_qipai_async_tasks_idempotency/);
+assert.match(asyncUpSql, /lease_expires_at DATETIME\(3\)/);
+assert.match(asyncUpSql, /COMPENSATION_REQUIRED|status VARCHAR/);
+
+console.log('PASS: M01-B/M01-C migration contracts are present.');

backend/tests/migration-runner.test.mjs

@@ -12,7 +12,8 @@ assert.deepEqual(
 
 const plan = await loadMigrationPlan('up');
 assert.equal(plan.direction, 'up');
-assert.match(plan.file, /2026061601_m01b_core_schema\.up\.sql$/);
+assert.match(plan.file, /2026061601_m01b_core_schema\.up\.sql/);
+assert.match(plan.file, /2026061802_m01c_async_tasks\.up\.sql$/);
 assert.match(plan.checksum, /^[a-f0-9]{64}$/);
 assert.ok(plan.statements.length >= 11);
 

backend/tests/mysql-migration-roundtrip.test.mjs

@@ -5,6 +5,7 @@ import { fileURLToPath } from 'node:url';
 import { loadConfig } from '../dist/config.js';
 import { closeMySqlPool, createMySqlPool } from '../dist/db/mysql.js';
 import { LegacyReadRepository } from '../dist/db/legacy-read-repository.js';
+import { TaskRepository } from '../dist/tasks/task-repository.js';
 import {
   executeMigrationPlan,
   loadMigrationPlan,
@@ -12,11 +13,13 @@ import {
 } from '../dist/db/migration-runner.js';
 
 const expectedTables = [
+  'qipai_async_tasks',
   'qipai_audit_logs',
   'qipai_devices',
   'qipai_legacy_table_mappings',
   'qipai_members',
   'qipai_orders',
+  'qipai_outbox_events',
   'qipai_payments',
   'qipai_rooms',
   'qipai_schema_migrations',
@@ -38,12 +41,13 @@ async function readCoreTables(pool) {
   return rows.map((row) => row.tableName);
 }
 
-async function readMigrationVersion(pool) {
+async function readMigrationVersions(pool) {
   const [rows] = await pool.query(
     `SELECT version, name
      FROM qipai_schema_migrations
-     WHERE version = ?`,
-    ['2026061601']
+     WHERE version IN (?, ?)
+     ORDER BY version`,
+    ['2026061601', '2026061802']
   );
   return rows;
 }
@@ -79,11 +83,48 @@ async function assertLegacyCompatibility(pool) {
   assert.equal(orders[0].refundAmountCents, null);
 }
 
+async function assertTaskDurability(pool) {
+  await pool.query(
+    `INSERT INTO qipai_tenants (code, name)
+     VALUES ('M01C-TEST', 'M01C sanitized test tenant')`
+  );
+  const firstRepository = new TaskRepository(pool);
+  const firstEnqueue = await firstRepository.enqueue({
+    tenantId: '1',
+    taskType: 'order.advance',
+    idempotencyKey: 'order:501:paid',
+    payload: { orderId: '501' },
+    maxAttempts: 3
+  });
+  const duplicateEnqueue = await firstRepository.enqueue({
+    tenantId: '1',
+    taskType: 'order.advance',
+    idempotencyKey: 'order:501:paid',
+    payload: { orderId: '501' },
+    maxAttempts: 3
+  });
+  assert.equal(firstEnqueue.created, true);
+  assert.equal(duplicateEnqueue.created, false);
+  assert.equal(duplicateEnqueue.id, firstEnqueue.id);
+
+  const restartedRepository = new TaskRepository(pool);
+  const claimed = await restartedRepository.claimNext('worker-after-restart', 30_000);
+  assert.equal(claimed?.id, firstEnqueue.id);
+  assert.equal(claimed?.attempts, 1);
+  assert.equal(await restartedRepository.complete(claimed.id, 'worker-after-restart'), true);
+
+  const [rows] = await pool.query(
+    `SELECT status, attempts FROM qipai_async_tasks WHERE id = ?`,
+    [firstEnqueue.id]
+  );
+  assert.deepEqual(rows, [{ status: 'SUCCEEDED', attempts: 1 }]);
+}
+
 const config = loadConfig();
 assert.equal(config.mysql.passwordConfigured, true, 'Live migration test requires a temporary password.');
 assert.match(
   config.mysql.database,
-  /^qipai_m01b_test_[a-z0-9_]+$/,
+  /^qipai_m01c_test_[a-z0-9_]+$/,
   'Live migration test refuses to use a non-temporary database.'
 );
 
@@ -102,25 +143,26 @@ try {
   await executeMigrationPlan(pool, plans.up);
   await executeMigrationPlan(pool, plans.verify);
   assert.deepEqual(await readCoreTables(pool), expectedTables);
-  assert.deepEqual(await readMigrationVersion(pool), [{
-    version: '2026061601',
-    name: 'm01b_core_schema'
-  }]);
+  assert.deepEqual(await readMigrationVersions(pool), [
+    { version: '2026061601', name: 'm01b_core_schema' },
+    { version: '2026061802', name: 'm01c_async_tasks' }
+  ]);
+  await assertTaskDurability(pool);
   await assertLegacyCompatibility(pool);
-  console.log('PASS: first up and verify completed.');
+  console.log('PASS: first up, verify and durable task restart check completed.');
 
   await executeMigrationPlan(pool, plans.down);
   assert.deepEqual(await readCoreTables(pool), []);
   await assertLegacyCompatibility(pool);
-  console.log('PASS: down removed all M01-B core tables.');
+  console.log('PASS: down removed all M01-B/M01-C tables.');
 
   await executeMigrationPlan(pool, plans.up);
   await executeMigrationPlan(pool, plans.verify);
   assert.deepEqual(await readCoreTables(pool), expectedTables);
-  assert.deepEqual(await readMigrationVersion(pool), [{
-    version: '2026061601',
-    name: 'm01b_core_schema'
-  }]);
+  assert.deepEqual(await readMigrationVersions(pool), [
+    { version: '2026061601', name: 'm01b_core_schema' },
+    { version: '2026061802', name: 'm01c_async_tasks' }
+  ]);
   await assertLegacyCompatibility(pool);
   console.log('PASS: second up and verify restored the schema.');
 

backend/tests/task-repository.test.mjs

@@ -0,0 +1,87 @@
+import assert from 'node:assert/strict';
+import { OutboxRepository } from '../dist/tasks/outbox-repository.js';
+import { retryDelayMs, taskTypes } from '../dist/tasks/task-repository.js';
+import { TaskWorker } from '../dist/tasks/worker.js';
+
+assert.deepEqual(taskTypes, [
+  'notification.dispatch',
+  'order.advance',
+  'device.command',
+  'refund.query',
+  'statistics.aggregate',
+  'outbox.publish'
+]);
+assert.equal(retryDelayMs(1), 1000);
+assert.equal(retryDelayMs(4), 8000);
+assert.equal(retryDelayMs(99), 60 * 60 * 1000);
+
+const outboxCalls = [];
+const outbox = new OutboxRepository({
+  async execute(sql, params) {
+    outboxCalls.push([sql, params]);
+    return [{ insertId: 7, affectedRows: 1 }, []];
+  }
+});
+assert.deepEqual(
+  await outbox.append({
+    tenantId: '1',
+    aggregateType: 'order',
+    aggregateId: '88',
+    eventType: 'order.paid',
+    idempotencyKey: 'order:88:paid',
+    payload: { orderId: '88' }
+  }),
+  { id: '7', created: true }
+);
+assert.match(outboxCalls[0][0], /INSERT IGNORE INTO qipai_outbox_events/);
+
+const calls = [];
+const task = {
+  id: '42',
+  tenantId: '1',
+  taskType: 'notification.dispatch',
+  idempotencyKey: 'notice:42',
+  payload: { channel: 'test' },
+  status: 'RUNNING',
+  attempts: 1,
+  maxAttempts: 3
+};
+const repository = {
+  async claimNext() {
+    calls.push('claim');
+    return task;
+  },
+  async complete(id) {
+    calls.push(`complete:${id}`);
+    return true;
+  },
+  async fail() {
+    calls.push('fail');
+  }
+};
+const worker = new TaskWorker({
+  repository,
+  handlers: new Map([['notification.dispatch', async (claimed) => {
+    calls.push(`handle:${claimed.id}`);
+  }]]),
+  workerId: 'test-worker'
+});
+assert.equal(await worker.runOnce(), true);
+assert.deepEqual(calls, ['claim', 'handle:42', 'complete:42']);
+
+const failedCalls = [];
+const failedWorker = new TaskWorker({
+  repository: {
+    async claimNext() { return task; },
+    async complete() { return true; },
+    async fail(claimed, workerId, error) {
+      failedCalls.push([claimed.id, workerId, error.message]);
+    }
+  },
+  handlers: new Map(),
+  workerId: 'test-worker'
+});
+assert.equal(await failedWorker.runOnce(), true);
+assert.deepEqual(failedCalls, [['42', 'test-worker', 'No handler registered for task type notification.dispatch.']]);
+
+console.log('PASS: M01-C task retry and worker contracts are present.');

database/migrations/2026061802_m01c_async_tasks.down.sql

@@ -0,0 +1,5 @@
+-- Roll back M01-C asynchronous task tables.
+
+DELETE FROM qipai_schema_migrations WHERE version = '2026061802';
+DROP TABLE IF EXISTS qipai_async_tasks;
+DROP TABLE IF EXISTS qipai_outbox_events;

database/migrations/2026061802_m01c_async_tasks.up.sql

@@ -0,0 +1,48 @@
+-- M01-C lightweight asynchronous task foundation.
+-- Tasks and outbox events are durable in MySQL and safe to resume after worker restarts.
+
+CREATE TABLE IF NOT EXISTS qipai_outbox_events (
+  id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  tenant_id BIGINT UNSIGNED NOT NULL,
+  aggregate_type VARCHAR(64) NOT NULL,
+  aggregate_id VARCHAR(64) NOT NULL,
+  event_type VARCHAR(128) NOT NULL,
+  idempotency_key VARCHAR(191) NOT NULL,
+  payload JSON NOT NULL,
+  status VARCHAR(32) NOT NULL DEFAULT 'PENDING',
+  available_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  published_at DATETIME(3) NULL,
+  attempts INT UNSIGNED NOT NULL DEFAULT 0,
+  last_error VARCHAR(1000) NULL,
+  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
+  CONSTRAINT fk_qipai_outbox_events_tenant FOREIGN KEY (tenant_id) REFERENCES qipai_tenants(id),
+  UNIQUE KEY uq_qipai_outbox_events_idempotency (tenant_id, idempotency_key),
+  KEY idx_qipai_outbox_events_dispatch (status, available_at, id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+CREATE TABLE IF NOT EXISTS qipai_async_tasks (
+  id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  tenant_id BIGINT UNSIGNED NOT NULL,
+  task_type VARCHAR(128) NOT NULL,
+  idempotency_key VARCHAR(191) NOT NULL,
+  payload JSON NOT NULL,
+  status VARCHAR(32) NOT NULL DEFAULT 'PENDING',
+  priority INT NOT NULL DEFAULT 0,
+  available_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  lease_owner VARCHAR(128) NULL,
+  lease_expires_at DATETIME(3) NULL,
+  attempts INT UNSIGNED NOT NULL DEFAULT 0,
+  max_attempts INT UNSIGNED NOT NULL DEFAULT 8,
+  last_error VARCHAR(1000) NULL,
+  completed_at DATETIME(3) NULL,
+  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
+  CONSTRAINT fk_qipai_async_tasks_tenant FOREIGN KEY (tenant_id) REFERENCES qipai_tenants(id),
+  UNIQUE KEY uq_qipai_async_tasks_idempotency (tenant_id, task_type, idempotency_key),
+  KEY idx_qipai_async_tasks_claim (status, available_at, priority, id),
+  KEY idx_qipai_async_tasks_lease (status, lease_expires_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+INSERT IGNORE INTO qipai_schema_migrations (version, name)
+VALUES ('2026061802', 'm01c_async_tasks');

database/migrations/2026061802_m01c_async_tasks.verify.sql

@@ -0,0 +1,29 @@
+-- Verify M01-C asynchronous task foundation.
+
+SELECT table_name
+FROM information_schema.tables
+WHERE table_schema = DATABASE()
+  AND table_name IN ('qipai_outbox_events', 'qipai_async_tasks')
+ORDER BY table_name;
+
+SELECT table_name, index_name
+FROM information_schema.statistics
+WHERE table_schema = DATABASE()
+  AND (
+    (table_name = 'qipai_outbox_events' AND index_name IN (
+      'uq_qipai_outbox_events_idempotency',
+      'idx_qipai_outbox_events_dispatch'
+    ))
+    OR
+    (table_name = 'qipai_async_tasks' AND index_name IN (
+      'uq_qipai_async_tasks_idempotency',
+      'idx_qipai_async_tasks_claim',
+      'idx_qipai_async_tasks_lease'
+    ))
+  )
+GROUP BY table_name, index_name
+ORDER BY table_name, index_name;
+
+SELECT version, name
+FROM qipai_schema_migrations
+WHERE version = '2026061802';

deploy/pm2/ecosystem.config.cjs

@@ -11,6 +11,18 @@ module.exports = {
         QIPAI_API_HOST: '127.0.0.1',
         QIPAI_API_PORT: '3001'
       }
+    },
+    {
+      name: 'qipai-worker',
+      cwd: '/opt/apps/qipai-backend/current/backend',
+      script: 'dist/tasks/worker.js',
+      instances: 1,
+      exec_mode: 'fork',
+      restart_delay: 3000,
+      kill_timeout: 10000,
+      env: {
+        NODE_ENV: 'production'
+      }
     }
   ]
 };

scripts/dev/windows/check-backend.ps1

@@ -11,6 +11,9 @@ $requiredFiles = @(
   "backend/src/db/migration-runner.ts",
   "backend/src/db/migrate-cli.ts",
   "backend/src/db/legacy-read-repository.ts",
+  "backend/src/tasks/task-repository.ts",
+  "backend/src/tasks/outbox-repository.ts",
+  "backend/src/tasks/worker.ts",
   "backend/src/routes/health.ts",
   "backend/src/server.ts",
   "backend/tests/backend-contract.test.mjs",
@@ -19,10 +22,14 @@ $requiredFiles = @(
   "backend/tests/migration-runner.test.mjs",
   "backend/tests/mysql-migration-roundtrip.test.mjs",
   "backend/tests/legacy-read-repository.test.mjs",
+  "backend/tests/task-repository.test.mjs",
   "scripts/dev/wsl/mysql-migration-roundtrip.sh",
   "database/migrations/2026061601_m01b_core_schema.up.sql",
   "database/migrations/2026061601_m01b_core_schema.down.sql",
   "database/migrations/2026061601_m01b_core_schema.verify.sql",
+  "database/migrations/2026061802_m01c_async_tasks.up.sql",
+  "database/migrations/2026061802_m01c_async_tasks.down.sql",
+  "database/migrations/2026061802_m01c_async_tasks.verify.sql",
   "database/seeds/2026061601_m01b_minimal_seed.sql",
   "deploy/pm2/ecosystem.config.cjs"
 )

scripts/dev/wsl/mysql-migration-roundtrip.sh

@@ -33,7 +33,7 @@ fi
 mysql --batch --skip-column-names -e 'SELECT CURRENT_USER()' >/dev/null
 
 run_id="$(date -u +%Y%m%d%H%M%S)_$$_$(openssl rand -hex 3)"
-database="qipai_m01b_test_${run_id}"
+database="qipai_m01c_test_${run_id}"
 username="qmb_$$_$(openssl rand -hex 4)"
 password="$(openssl rand -hex 24)"
 created=0
@@ -63,7 +63,7 @@ if [[ "${1:-}" == "--force-failure" ]]; then
 fi
 
 if [[ "${1:-}" == "--cleanup-probe" ]]; then
-  before_database_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM information_schema.SCHEMATA WHERE SCHEMA_NAME LIKE 'qipai_m01b_test_%'")"
+  before_database_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM information_schema.SCHEMATA WHERE SCHEMA_NAME LIKE 'qipai_m01c_test_%'")"
   before_user_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM mysql.user WHERE User LIKE 'qmb_%' AND Host = '127.0.0.1'")"
   set +e
   bash "${BASH_SOURCE[0]}" --force-failure
@@ -73,7 +73,7 @@ if [[ "${1:-}" == "--cleanup-probe" ]]; then
     echo "FAIL: cleanup probe did not produce the expected interrupted status." >&2
     exit 1
   }
-  after_database_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM information_schema.SCHEMATA WHERE SCHEMA_NAME LIKE 'qipai_m01b_test_%'")"
+  after_database_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM information_schema.SCHEMATA WHERE SCHEMA_NAME LIKE 'qipai_m01c_test_%'")"
   after_user_count="$(mysql --batch --skip-column-names -e "SELECT COUNT(*) FROM mysql.user WHERE User LIKE 'qmb_%' AND Host = '127.0.0.1'")"
   if [[ "${before_database_count}" != "${after_database_count}" || "${before_user_count}" != "${after_user_count}" ]]; then
     echo "FAIL: temporary MySQL resources survived an interrupted test." >&2
@@ -93,6 +93,6 @@ export QIPAI_MYSQL_USER="${username}"
 export QIPAI_MYSQL_PASSWORD="${password}"
 export QIPAI_MYSQL_CONNECTION_LIMIT=2
 
-echo "INFO: MySQL ${mysql_version}; running M01-B migration roundtrip in a temporary database."
+echo "INFO: MySQL ${mysql_version}; running M01-B/M01-C migration roundtrip in a temporary database."
 npm --prefix backend run test:mysql:migration
-echo "PASS: M01-B live MySQL migration roundtrip completed."
+echo "PASS: M01-B/M01-C live MySQL migration roundtrip completed."