Move to file_picker v13 and device_info_plus v13 (win32 v6)

Both depend on win32 v6, like current Serverpod, so an app that also uses Serverpod can resolve the editor in one pub workspace; file_picker v10 and device_info_plus v12 need win32 v5.

file_picker v12 made its API static, returns the picked files directly and reads their content on demand (PlatformFile.readAsBytes()); v13 removed the parameters v12 had deprecated. The FilePickerService implementation keeps its interface: withData, withReadStream and lockParentWindow are ignored, allowMultiple chooses between pickFiles() and pickFile(), and saveFile() saves an empty file, since file_picker now writes the file itself and needs its content up front. The image upload reads the picked file's bytes on the web; the example app saves and opens files with the new API.

Raises the minimum to Dart v3.11 and Flutter v3.41.6 (device_info_plus v13).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pubspec.yaml

@@ -5,17 +5,17 @@ version: 6.1.0
 homepage: "https://github.com/AppFlowy-IO/appflowy-editor"
 
 environment:
-  sdk: ">=3.6.0 <4.0.0"
-  flutter: ">=3.32.0"
+  sdk: ">=3.11.0 <4.0.0"
+  flutter: ">=3.41.6"
 
 description: A highly customizable rich-text editor for Flutter. The AppFlowy
   Editor project for AppFlowy and beyond.
 
 dependencies:
   collection: "^1.18.0"
-  device_info_plus: ^12.3.0
+  device_info_plus: ^13.2.0
   diff_match_patch: "^0.4.1"
-  file_picker: ^10.3.10
+  file_picker: ^13.1.0
   flutter:
     sdk: flutter
   flutter_svg: "^2.0.6"