fix: address texture watchdog/probe review findings

- watchdog: compare the plugin's cumulative consumed counter against a
  snapshot taken when arming (re-arm was a no-op before), and judge on
  cumulative pushes + elapsed time so sparse damage-driven streams are
  still detected
- failure handling is idempotent (one record per breakage) and updates
  every render session like main_set_local_option does, not only the
  failing one; the fallback toast is not claimed for multi-display
  windows the soft path cannot rescue
- probe: skip when the consumed API is missing (old plugin) or a
  raster-stall is recorded (compositing could hang the main window);
  a fail verdict requires fresh frame timings and a non-minimized
  window; a pass never clears failed-raster-stall; toast only when
  texture rendering was effectively on; probe pixel is transparent
- raster-stall monitor: judge on frame-timing staleness (a mid-episode
  hang was undetectable before), gate on lifecycle/minimized/idle with
  a moving quiet anchor, threshold 30s, shared with the camera page;
  clear stateGlobal minimized flag on plain window restore
- adopt mismatched frame sizes only in multi-ui-session mode (legacy
  mode pairs frames loosely and could ping-pong between displays)
- drop the now-dead closeSession parameter from texture destroy();
  trim comments to repo style

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

flutter/lib/desktop/pages/view_camera_page.dart

@@ -19,6 +19,7 @@ import '../../common/shared_state.dart';
 import '../../utils/image.dart';
 import '../widgets/remote_toolbar.dart';
 import '../widgets/kb_layout_type_chooser.dart';
+import '../widgets/raster_stall_monitor.dart';
 import '../widgets/tabbar_widget.dart';
 
 import 'package:flutter_hbb/native/custom_cursor.dart'
@@ -102,6 +103,7 @@ class _ViewCameraPageState extends State<ViewCameraPage>
     super.initState();
     _ffi = FFI(widget.sessionId);
     Get.put<FFI>(_ffi, tag: widget.id);
+    RasterStallMonitor.start();
     _ffi.imageModel.addCallbackOnFirstImage((String peerId) {
       showKBLayoutTypeChooserIfNeeded(
           _ffi.ffiModel.pi.platform, _ffi.dialogManager);
@@ -222,7 +224,7 @@ class _ViewCameraPageState extends State<ViewCameraPage>
     // https://github.com/flutter/flutter/issues/64935
     super.dispose();
     debugPrint("VIEW CAMERA PAGE dispose session $sessionId ${widget.id}");
-    _ffi.textureModel.onViewCameraPageDispose(closeSession);
+    _ffi.textureModel.onViewCameraPageDispose();
     if (closeSession) {
       // ensure we leave this session, this is a double check
       _ffi.inputModel.enterOrLeave(false);