feat: scaffold worker application shell

Adds apps/worker with TypeScript config, BullMQ/ioredis dependencies,
pino logger bootstrap, and a smoke test. Queue consumers wired in later phases.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/worker/jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  testMatch: ['**/*.test.ts'],
+  rootDir: 'src',
+};