fix: swallow async opifex MQTT socket close rejection (node crash loop)

[Yiakman]

The real cause of the node crash loop after #8/#9 — and it's not game logic, witnesses, or the contract. It's the in-process MQTT engine.

Diagnosis

With both witnesses objects fixed, the node initialized cleanly but still exit(1)'d ~12s in, silently (no stack). I instrumented it with a process.exit/unhandledRejection probe (bun --preload) and captured:

TypeError: Cannot close a writable stream that is closed or errored
  at close (@seriousme/opifex/dist/socket/socket.js:33)   ← this.writer.close()
  at close (.../mqttConn/mqttConn.js:171)
  at #receive (.../mqttConn/mqttConn.js:131)              ← MQTT client teardown
→ unhandledRejection → @effectstream/log process-handlers.ts:48 → process.exit(1)

opifex's close() already tries to swallow close errors:

close() {
  if (!this.closed) {
    try { this.writer.close(); } catch (_err) { /* swallow */ }   // ← line 33

…but WritableStreamDefaultWriter.close() returns a Promise that rejects asynchronously when the stream is already closed/errored. A synchronous try/catch can't catch that, so the rejection floats up. Under bun, effectstream's unhandledRejection handler turns it into process.exit(1). (Under deno this was tolerated — which is why it only became fatal after the bun migration. The skip-ahead to realtime made MQTT teardowns frequent → constant crash loop.)

Fix

In patch.sh (the existing post-install node_modules patcher, already used for hardhat + fetch-blob), rewrite this.writer.close(); → this.writer.close().catch(() => {}); in opifex's socket. Completes the swallow the code already intended, for the async case. Idempotent; covers both bun-hoisted and npm-hoisted layouts.

Validation

Root-caused from the live stack trace + source. I was not able to runtime-validate on the box (direct node_modules edits there are blocked by policy). After merge I'll pull on the box, re-run, and confirm the node stays up past the crash point and processes live events — and report back before declaring go-fish healthy.

🤖 Generated with Claude Code