Sync with core 6dfa108: replay the window_manager reports on Windows (#76, #77, #78)

tools/gui/flutter_window_reports_test.ps1 builds tools/gui/
window_reports_flutter.dart against the workspace's Dart packages and
replays the reports carried over from window_manager in a real Flutter
Windows app, measuring geometry, styles, caption buttons, pixels and
frames. All 15 covered reports behave on core 6dfa108; it found
Application::SetIcon doing nothing on Windows (fixed there).

Author: lijy91

core

@@ -22,6 +22,7 @@ runner) lives in [`.agents/skills/`](../../.agents/skills); read
 | `flutter_window_title_bar_system_menu_test.ps1` | `window_title_bar_example` (#66) | Windows | End to end in a real Flutter app: a secondary click on the `DragToMoveArea` strip opens the native system menu at the pointer; its item states match the window (restored: Restore off; maximized: Move, Size, Maximize off); choosing Maximize maximizes and, from a second menu, Restore restores to the earlier width. Items are taken by their fixed order, so any display language works. Owner-guarded clicks, no keyboard. Set `TITLE_BAR_EXAMPLE_EXE` for a build outside `$RemoteWorkspace`. |
 | `flutter_window_title_bar_close_test.ps1` | `window_title_bar_example` (#65) | Windows | End to end in a real Flutter app: with Closing set to Keep open, the example cancels `WindowCloseRequestedEvent`; a real click on the window's own close button (found through DWM's caption button bounds) and the system menu's Close each leave the window open and count one cancelled request; with Allow, the close button closes the window and the app exits with code 0. Owner-guarded clicks, no keyboard. Set `TITLE_BAR_EXAMPLE_EXE` for a build outside `$RemoteWorkspace`. |
 | `flutter_window_title_bar_close_test_linux.py` | `window_title_bar_example` (#65) | Linux (GNOME) | The Linux twin of the close test: with Keep open, two real clicks on the header bar's close button (found by its accessible name through AT-SPI) are cancelled and counted; with Allow the click closes the window and the app exits with code 0. The Flutter view is located through AT-SPI too, since the runner's header bar sits inside the X11 client area. The system menu is gnome-shell's and is not driven. Set `TITLE_BAR_EXAMPLE_EXE` for a build outside `$REMOTE_WORKSPACE`. |
+| `flutter_window_reports_test.ps1` | fixture `window_reports_flutter.dart` (#76, #77, #78) | Windows | The window_manager reports carried over to nativeapi-core, replayed through the Flutter Window API in a fixture app built from the workspace's Dart packages (`REPORTS_ARCHIVE`). The app paints solid colours and announces each step; the runner measures geometry, styles, DWM caption buttons, pixels and frame-by-frame samples. Scenarios (`REPORTS_SCENARIOS`): `fullscreen` (#458 start in full screen and leave it, #579 caption back, #330 no stale content at the bottom), `hidden` (#547 top border as thick as the sides, #554/#450 maximized exactly to the work area, #378 no padding in full screen, #397 no caption flash when leaving it), `transparent` (#576 caption buttons and title with a transparent background), `events` (#294 focus last after restoring, #207 double-click on the caption maximizes and restores with Resized, #511 maximize() from onDoubleTapDown, #534 setIcon() from flutter_assets). Owner-guarded clicks on the app's own window only, no keyboard. Not covered: #480 (keyboard) and #245 (two monitors). |
 | `core_window_shadow_layout_test_linux.cpp` | core shadow | Linux Wayland / X11 | No-input regression: stable shadow geometry, contour pixels inside transparent content, input pass-through, disable and decoration restoration |
 | `flutter_window_shape_smoke_macos.py` / `flutter_window_shape_test_windows.ps1` | `shaped_window_example` | macOS / Windows | macOS: no-input shape and pixel-alpha smoke test; Windows: native regions, real button clicks/drag, resize, clear/reapply, click-through to the underlying app window |
 | `flutter_detachable_window_test.py` / `.ps1` | `detachable_window_example` | macOS / Windows | tear a panel off, exact content size, header stays under the cursor, dock into the other window, `State` preserved |