Track intermittent segfault with @vekexasia/bigint-buffer2 on Node 24

## Summary
Intermittent native segfault observed while running Lodestar with `@vekexasia/bigint-buffer2@1.1.0` on Node.js v24.

This is a downstream tracking issue to document repro conditions and link upstream findings.

## Environment
- Lodestar: v1.40.0
- Node.js: v24.x
- Package: `@vekexasia/bigint-buffer2@1.1.0`

## Upstream context
- bigint-swissknife issue: https://github.com/vekexasia/bigint-swissknife/issues/5

## Current status
- Native audit found a potential memory-safety bug in `BufferMut` when a null pointer is paired with non-zero length.
- Reachability from Lodestar hot path is still being validated.
- Node version mismatch remains a competing hypothesis.

We'll update this issue with a minimized repro and stack traces as investigation continues.