Poollet: gRPC client discards `list` operations when exhausting message body receive size

[balpert89]

Describe the bug

When dealing with a large amount of resources that a poollet instance manages (e.g. Volume for a volumepoollet) the gRPC client implementation will discard the result of list operations:

2026-01-29T14:37:22.429106952Z	ERROR	event-generator	Error relisting	{"error": "error listing: rpc error: code = ResourceExhausted desc = grpc: received message larger than max (4239787 vs. 4194304)"}
github.com/onmetal/onmetal-api/poollet/orievent.(*generator[...]).Start.func2
	/workspace/poollet/orievent/generator.go:231

The default size for received messages is 4194304 (1024*1024*4).

To Reproduce

1. create 7k Volume resources
2. let Volumepoollet reconcile the amount of resources
3. observe log output on Volumepoollet side

Expected behavior
The poollet instance can handle more than the described amount of resources.

[balpert89]

There are several ideas for long-term improvements on the poollet side:

• pagination
• streaming

Those are not first-class citizens in the grpc upstream implementation and need to be implemented on our side.

We have provided a hotfix and I will provide a draft PR to unblock in the meantime until we decided how to proceed with the solution.