refactor(app): Material from material_ui instead of the SDK

Flutter 3.47 moved Material and Cupertino out of the SDK into material_ui and cupertino_ui, which ship weekly. The SDK imports are deprecated from the November 2026 stable release and removed in 2027, and the strict pre-push check would block every push then. The app's one Material import now comes from material_ui ^1.5.0, so everything built from here on uses the new import.

Packages that still import package:flutter/material.dart (Serverpod's Flutter packages, later the rich-text editor) see the app's theme and localizations only through MaterialUiCompatibilityBridge, set in MaterialApp.builder. The bridge is deprecated on purpose, as a reminder to remove it, so its use carries a documented ignore until those packages have moved.

google_fonts is removed: it was unused, and by default it downloads fonts from Google at runtime, which sends every user's IP address to Google.

AGENTS.md: Material comes from material_ui.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

AGENTS.md

@@ -77,6 +77,7 @@ A spaced-repetition learning app: studysets of flashcards, reviewed on an FSRS s
 - **Time comes from `clock.now()`** (`package:clock`), never `DateTime.now()`, in server and app. Why: scheduling, streaks and expiry are deterministic under test (`withClock`, `fakeAsync`), and because Serverpod itself reads `clock.now()` (e.g. session expiry), `withClock` controls its behaviour too.
 - **UTC for storing and sending, local time for display and day boundaries.** Serverpod sends `DateTime` as UTC and stores it in `timestamp without time zone` columns. Compare and compute in UTC; call `.toLocal()` only to display. "Due today", streaks and daily goals use the learner's **local** calendar day, computed on the client; the server never needs day boundaries.
 - **Build configuration comes from `--dart-define`.** The client holds no secrets, ever.
+- **Material comes from `package:material_ui`** (Cupertino from `package:cupertino_ui`), never from `package:flutter/material.dart`, which Flutter deprecates from its November 2026 release on. Packages still on the SDK's copy get the app's theme and localizations through `MaterialUiCompatibilityBridge` in `MaterialApp.builder`; remove it once they have moved.
 
 ## Testing
 

halkyon_learn_flutter/lib/main.dart

@@ -1,6 +1,5 @@
-import 'package:flutter/material.dart';
-
 import 'package:halkyon_learn_flutter/client.dart';
+import 'package:material_ui/material_ui.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -25,6 +24,12 @@ class const HalkyonLearnApp({super.key}) extends StatelessWidget {
       title: 'Halkyon Learn',
       theme: _buildTheme(Brightness.light),
       darkTheme: _buildTheme(Brightness.dark),
+      // Packages that still import package:flutter/material.dart (Serverpod's sign-in
+      // widgets, the rich-text editor) see this app's theme and localizations only
+      // through the bridge, since material_ui is a separate copy of that library. The
+      // bridge is deprecated on purpose, as a reminder: remove it once they have moved.
+      // ignore: deprecated_member_use
+      builder: (context, child) => MaterialUiCompatibilityBridge(child: child!),
       home: Scaffold(appBar: AppBar(title: const Text('Halkyon Learn'))),
     );
   }

halkyon_learn_flutter/pubspec.yaml

@@ -29,9 +29,9 @@ dependencies:
   cupertino_icons: ^1.0.5
   flutter:
     sdk: flutter
-  google_fonts: ^8.1.0
   halkyon_learn_client:
     path: ../halkyon_learn_client
+  material_ui: ^1.5.0
   serverpod_auth_idp_flutter: 4.0.2
   serverpod_flutter: 4.0.2
 

pubspec.lock

@@ -201,6 +201,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.9"
+  cupertino_ui:
+    dependency: transitive
+    description:
+      name: cupertino_ui
+      sha256: c23816577a1280cff409e989541767887011f8f1d8c1863a794ed308af46f2a9
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.1"
   dart_jsonwebtoken:
     dependency: transitive
     description:
@@ -623,6 +631,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.13.0"
+  material_ui:
+    dependency: transitive
+    description:
+      name: material_ui
+      sha256: "32d98f11cf5942a095a8c3e01b03e4de3b17941437713dcf36b1088fb62e23d2"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
   meta:
     dependency: transitive
     description:
@@ -1462,4 +1478,4 @@ packages:
     version: "2.2.4"
 sdks:
   dart: ">=3.13.0 <4.0.0"
-  flutter: ">=3.44.4 <4.0.0"
+  flutter: ">=3.47.0 <4.0.0"