| App | Application entry point and process-wide composition root. `OnLaunched` resolves the engine boundary (EngineClient) and stands up the single MainWindow. On fatal init failure it falls back to `FakeEngineClient` to avoid crashing silently. |
| MainPage | Wiring only: builds the ViewModel graph and connects view events to it. Imperative ListView work (viewport/selection restore, row actions) lives in ResultsViewportManager; the F12 panel chrome in PerfPanel; converters in UiConverters. |
| MainWindow | The application window: hosts the root Frame; app UI lives in MainPage. |
| Program | Program class |