feat(adminui): driver-snapshot GetAll() + pure Hosts driver-view builder (#8)

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/IDriverStatusSnapshotStore.cs

@@ -14,6 +14,9 @@ public interface IDriverStatusSnapshotStore
     void Upsert(DriverHealthChanged snapshot);
     bool TryGet(string driverInstanceId, out DriverHealthChanged snapshot);
 
+    /// <summary>Returns a point-in-time snapshot of every driver instance's last-known health.</summary>
+    IReadOnlyCollection<DriverHealthChanged> GetAll();
+
     /// <summary>
     ///     Raised after every <see cref="Upsert"/> with the just-stored snapshot. Lets in-process
     ///     consumers (the Blazor Server <c>DriverStatusPanel</c>) receive live updates by reading

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Hubs/InMemoryDriverStatusSnapshotStore.cs

@@ -25,4 +25,7 @@ public sealed class InMemoryDriverStatusSnapshotStore : IDriverStatusSnapshotSto
     /// <inheritdoc />
     public bool TryGet(string driverInstanceId, out DriverHealthChanged snapshot)
         => _byInstance.TryGetValue(driverInstanceId, out snapshot!);
+
+    /// <inheritdoc />
+    public IReadOnlyCollection<DriverHealthChanged> GetAll() => _byInstance.Values.ToArray();
 }