Log outgoing HTTP requests made by user components

## Request

Harper components can make outgoing HTTP requests, but there is currently no built-in logging for those requests. Since we don't have access to customer component code, we cannot insert logging at the call site.

## Approach

Research and implement one of:
1. **Node.js Diagnostics Channel API** — `require('diagnostics_channel')` can hook into `http` and `https` channels to observe outgoing requests without monkey-patching
2. **Monkey-patch** — wrap `http.request`/`https.request` to intercept and log

Ideally, log:
- Outgoing method, URL, headers (redacted as needed), response status + timing
- Correlation with the incoming request that triggered it (thread/request ID)

This improves debuggability for customer-reported latency and connectivity issues where the cause is an outgoing call from user code.

🤖 Filed by Claude on behalf of Kris.