v2.1.0

• Fixed: an unsendable handler error no longer kills the worker isolate and hangs compute() — it is delivered as a RemoteError fallback.
• Fixed: worker isolates are monitored via onExit/onError — unexpected death fails in-flight compute() calls with a descriptive error and the pool re-spawns a fresh isolate on the next call.
• Fixed: an unsendable input to compute() no longer leaks the reply port or causes an unhandled async error on a later dispose().