Implement Galaxy filters and API key constraints

clients/dotnet/README.md

@@ -164,6 +164,19 @@ foreach (GalaxyObject galaxyObject in objects)
 }
 ```
 
+Use `DiscoverHierarchyOptions` to request a server-side slice without pulling
+the full Galaxy:
+
+```csharp
+IReadOnlyList<GalaxyObject> pumps = await repository.DiscoverHierarchyAsync(
+    new DiscoverHierarchyOptions
+    {
+        RootContainedPath = "Area1/Line3",
+        TagNameGlob = "Pump_*",
+        IncludeAttributes = false,
+    });
+```
+
 The CLI exposes the same operations:
 
 ```powershell