- Add integration test for per-destination thread_id resolution: seeds two destinations with different thread IDs, verifies each outbound message carries the correct thread_id (not a global one from the batch routing). - Add log line in resolveDestinationThread catch block for debuggability. - Remove stray "(ensurePreCompactHook is defined after the main function.)" comment from group-init.ts. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>