WebClient: 3.44 webcodecs offline (#15722)

* feat(web): zero-readback WebCodecs video path

Decoded VideoFrames from js/src/webcodecs.js are handed to Flutter via
window.onVideoFrame and imported GPU-side with createImageFromTextureSource;
any failure unregisters the hook so the JS side falls back to RGBA readback.

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

* fix(web): load bundled terminal font when Google CDNs are unreachable

In air-gapped deployments GoogleFonts.robotoMono() cannot download the
terminal font; when index.html signals offline mode, load the copy bundled
with the web app under the family name google_fonts registers.

Part of the fix for rustdesk/rustdesk-server-pro#996.

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

* ci: bump windows arm64 to Flutter 3.44.8, add web build patch script

apply_flutter_3.44_web_patches.sh prepares a 3.44.x web build on top of the
shared source patches: qr_code_scanner's web impl needs dart:ui_web for the
removed platformViewRegistry, and flutter/web/fonts is refreshed to the font
paths the 3.44 engine requests. The disabled build-rustdesk-web job runs it
automatically once FLUTTER_VERSION moves to 3.44.x, and version-guarded
'Patch flutter' steps no longer fail when the guard does not match.

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

* fix(web): prevent stale WebCodecs frames across sessions

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(web): harden WebCodecs reconnect and Flutter 3.44 patches

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(ci): harden Flutter 3.44 patch input validation

Validate required files before checking patch state,
parameterize the theme-range validator, and prevent
missing inputs from satisfying NO_MATCHES checks.

Signed-off-by: fufesou <linlong1266@gmail.com>

* Remove unused code

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(web): retry font loading and dispose stale decoded images

Signed-off-by: fufesou <linlong1266@gmail.com>

* remove unused code

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(web): Bad state: RenderBox was not laid out

Signed-off-by: fufesou <linlong1266@gmail.com>

---------

Signed-off-by: fufesou <linlong1266@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: fufesou <linlong1266@gmail.com>

flutter/lib/models/web_model.dart

@@ -2,14 +2,18 @@
 
 import 'dart:convert';
 import 'dart:js_interop';
+import 'dart:js_interop_unsafe';
 import 'dart:typed_data';
 import 'dart:js';
 import 'dart:html';
 import 'dart:async';
+import 'dart:ui' as ui;
+import 'dart:ui_web' as ui_web;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter_hbb/common/widgets/login.dart';
 import 'package:flutter_hbb/models/state_model.dart';
+import 'package:flutter_hbb/models/web_video_frame_queue.dart';
 
 import 'package:flutter_hbb/web/bridge.dart';
 import 'package:flutter_hbb/common.dart';
@@ -18,6 +22,22 @@ import 'package:uuid/uuid.dart';
 final List<StreamSubscription<MouseEvent>> mouseListeners = [];
 final List<StreamSubscription<KeyboardEvent>> keyListeners = [];
 
+// WebCodecs VideoFrames handed over from js/src/webcodecs.js arrive as plain
+// interop objects (the package language version predates extension types).
+// This side owns each frame and must close it quickly: hardware decoders
+// stall once their small output frame pool is exhausted.
+int _videoFrameWidth(JSObject frame) =>
+    frame.getProperty<JSNumber>('displayWidth'.toJS).toDartInt;
+int _videoFrameHeight(JSObject frame) =>
+    frame.getProperty<JSNumber>('displayHeight'.toJS).toDartInt;
+void _closeVideoFrame(JSObject frame) {
+  try {
+    frame.callMethod<JSAny?>('close'.toJS);
+  } catch (error) {
+    debugPrint('VideoFrame.close failed: $error');
+  }
+}
+
 typedef HandleEvent = Future<void> Function(Map<String, dynamic> evt);
 
 class PlatformFFI {
@@ -33,6 +53,13 @@ class PlatformFFI {
   }
 
   PlatformFFI._() {
+    _videoFrameQueue = WebVideoFrameQueue(
+      importFrame: _importVideoFrame,
+      closeFrame: _closeVideoFrame,
+      disposeImage: (image) => image.dispose(),
+      onImportError: _handleVideoFrameImportError,
+      onCallbackError: _handleVideoImageCallbackError,
+    );
     window.document.addEventListener(
         'visibilitychange',
         (event) => {
@@ -162,6 +189,46 @@ class PlatformFFI {
     };
   }
 
+  late final WebVideoFrameQueue<JSObject, ui.Image> _videoFrameQueue;
+
+  // Zero-readback video path: the JS decoder hands decoded VideoFrames here
+  // (checking typeof window.onVideoFrame before every frame), and the engine
+  // imports them GPU-to-GPU via createImageBitmap. Unregistering the JS global
+  // reverts the JS side to the RGBA readback path.
+  void setVideoFrameCallback(
+      Future<void> Function(int, ui.Image, bool Function()) fun) {
+    _videoFrameQueue.beginSession(fun);
+    if (!_videoFrameQueue.isEnabled) return;
+    globalContext.setProperty(
+      'onVideoFrame'.toJS,
+      ((JSNumber display, JSObject frame) {
+        _videoFrameQueue.submit(display.toDartInt, frame);
+      }).toJS,
+    );
+  }
+
+  void clearVideoFrameCallback() {
+    _videoFrameQueue.endSession();
+    globalContext.setProperty('onVideoFrame'.toJS, null);
+  }
+
+  Future<ui.Image> _importVideoFrame(JSObject frame) async {
+    return await ui_web.createImageFromTextureSource(frame,
+        width: _videoFrameWidth(frame), height: _videoFrameHeight(frame));
+  }
+
+  void _handleVideoFrameImportError(Object error, StackTrace stackTrace) {
+    debugPrintStack(
+        label: 'createImageFromTextureSource failed, using RGBA path: $error',
+        stackTrace: stackTrace);
+    globalContext.setProperty('onVideoFrame'.toJS, null);
+  }
+
+  void _handleVideoImageCallbackError(Object error, StackTrace stackTrace) {
+    debugPrintStack(
+        label: 'video image callback error: $error', stackTrace: stackTrace);
+  }
+
   void startDesktopWebListener() {
     mouseListeners.add(
         window.document.onContextMenu.listen((evt) => evt.preventDefault()));