Fix lifecycle tests after batched store merge

[ctoth]

Summary

• await the documented microtask delivery boundary in the two lifecycle tests added by PR Replace manual disconnect teardown with owner resets #91
• preserve the batched output and channel-history store behavior introduced on master
• make the master Node.js CI test contract deterministic again

Root cause

PR #91 was merged from a stale base after output and channel-history appends had become microtask-batched. Its two new synchronous assertions therefore observed the pre-flush empty snapshots on the merge result, although the production stores behaved as designed.

Validation

• exact tracked CI inventory: 108 test files, 1,081 tests passed
• targeted regressions: 2 files, 35 tests passed
• npm run typecheck
• Biome lint on both changed files
• git diff --check