feat(caddystorage): simplify CaddyStorage gRPC API to allow only one2one calls

pkg/client/machine.go

@@ -141,3 +141,23 @@ func (cli *Client) WaitClusterReady(ctx context.Context, timeout time.Duration)
 	}
 	return backoff.Retry(listMachines, boff)
 }
+
+// WaitForStoreVersion waits until the cluster store on the target machine has reached each requested actor version
+// in minVersion, with no known missing or pending transactions through those versions.
+// The context controls cancellation and the deadline. An empty minVersion requires no replication.
+// This method observes replication without initiating synchronisation.
+//
+// Corrosion may satisfy a version by applying its surviving changes or by marking it complete because its changes
+// have been superseded.
+//
+// Waiting normally makes the captured data available on the machine. However, another write may replace some of that
+// data before it arrives. Corrosion can then complete the older version without transferring the replaced data.
+// If the replacement is outside the requested versions, this method can succeed while the affected data is still
+// missing or outdated. This can happen during concurrent updates even when all machines are well connected.
+//
+// Success does not guarantee an exact snapshot or delivery of every historical value.
+// Callers that require a specific record or condition should verify it after waiting.
+func (cli *Client) WaitForStoreVersion(ctx context.Context, minVersion map[string]uint64) error {
+	_, err := cli.MachineClient.WaitForStoreVersion(ctx, &pb.WaitForStoreVersionRequest{MinVersion: minVersion})
+	return err
+}