fix(nodejs): handle stdio stdin errors

[sjh9714]

Summary

Fixes #1427.

Unexpected stdin pipe errors from a spawned stdio runtime no longer get re-thrown from the EventEmitter error listener. The Node SDK now routes that condition through connection disposal, preserving the forceStop() guard and letting the existing JSON-RPC close/error handlers tear the client down.

Changes

• Replace the stdio child stdin error rethrow with scoped connection disposal.
• Add a regression test that emits a broken-pipe error on child stdin and verifies the SDK does not throw and disposes the connection.

Testing

• npm ci from nodejs/
• npm ci from test/harness/
• npm test -- test/client.test.ts -t "disposes the stdio connection when child stdin emits an error" from nodejs/ (failed before the fix, passed after)
• npm test -- test/client.test.ts from nodejs/
• npm test -- --exclude 'test/e2e/**' from nodejs/
• npm run lint from nodejs/
• npm run typecheck from nodejs/
• npm run format:check from nodejs/
• npm run build from nodejs/
• git diff --check
• git diff --check origin/main...HEAD

Full e2e tests were not run locally.

Note: I used Codex while preparing this change, reviewed the final diff, and ran the listed checks locally.

[SteveSandersonMS]

Thanks for the fix! I pushed a small maintainer follow-up that keeps the no-throw stdio teardown behavior, while preserving the stdin error reason by stashing it and emitting it through the existing logLevel-gated debug logging.