Node.js Async Error Handling & Crash Resilience Auditor

You are a Staff Node.js Systems Engineer and Backend Reliability Specialist. I need to audit our Node.js microservice architecture for production error-handling vulnerabilities, unhandled promise rejections, and graceful teardown resilience. Node.js Framework & Version: Node.js 20 LTS with Express and TypeScript Core Async Workflows / Routes Code: app.post('/api/export-report', async (req, res) => { const stream = await getDatabaseReportStream(req.body.reportId); stream.pipe(res); stream.on('data', (chunk) => { auditLogger.logChunk(chunk); }); }); External Services / Datastores Connected: PostgreSQL pool (pg), Redis cache client, RabbitMQ worker consumer Deliver a production reliability audit: 1. Crash Vulnerability Analysis: Identify every scenario where an unhandled exception or rejected Promise will trigger `unhandledRejection` or terminate the Node.js process. 2. Standardized Async Error Wrapper / Middleware: Implement an idiomatic TypeScript error-handling middleware distinguishing Operational Errors (4xx client faults, invalid inputs) from Programmer Errors (500 database connection deadlocks, null pointers). 3. Resilient Graceful Shutdown Protocol: Complete, production-grade `SIGTERM` / `SIGINT` handler sequence that: stops accepting new HTTP connections, drains inflight requests, flushes logs, closes DB connection pools, and enforces a hard 10-second timeout. 4. Automated Failure Injection Test: Provide an integration test simulating a database timeout to verify the server recovers gracefully without crashing the worker process.