feat: align iOS client safety and consent experience

health_app/lib/providers/ai_consent_provider.dart

@@ -6,22 +6,18 @@ const aiConsentVersion = 'ai-data-consent-v1';
 
 class AiConsentState {
   final bool isLoading;
+  final bool isSaving;
   final bool granted;
   final String? userId;
+  final String? error;
 
   const AiConsentState({
     this.isLoading = true,
+    this.isSaving = false,
     this.granted = false,
     this.userId,
+    this.error,
   });
-
-  AiConsentState copyWith({bool? isLoading, bool? granted, String? userId}) {
-    return AiConsentState(
-      isLoading: isLoading ?? this.isLoading,
-      granted: granted ?? this.granted,
-      userId: userId ?? this.userId,
-    );
-  }
 }
 
 final aiConsentProvider = NotifierProvider<AiConsentNotifier, AiConsentState>(
@@ -36,21 +32,62 @@ class AiConsentNotifier extends Notifier<AiConsentState> {
 
   Future<void> load(String userId) async {
     state = AiConsentState(isLoading: true, userId: userId);
-    final value = await ref.read(localDbProvider).read(_key(userId));
+    try {
+      final value = await ref.read(localDbProvider).read(_key(userId));
+      state = AiConsentState(
+        isLoading: false,
+        granted: value == 'granted',
+        userId: userId,
+      );
+    } catch (_) {
+      state = AiConsentState(
+        isLoading: false,
+        userId: userId,
+        error: 'Authorization status could not be loaded.',
+      );
+    }
+  }
+
+  Future<bool> grant(String userId) async {
     state = AiConsentState(
       isLoading: false,
-      granted: value == 'granted',
+      isSaving: true,
+      granted: state.granted,
       userId: userId,
     );
+    try {
+      await ref.read(localDbProvider).write(_key(userId), 'granted');
+      state = AiConsentState(isLoading: false, granted: true, userId: userId);
+      return true;
+    } catch (_) {
+      state = AiConsentState(
+        isLoading: false,
+        userId: userId,
+        error: 'Authorization could not be saved.',
+      );
+      return false;
+    }
   }
 
-  Future<void> grant(String userId) async {
-    await ref.read(localDbProvider).write(_key(userId), 'granted');
-    state = AiConsentState(isLoading: false, granted: true, userId: userId);
-  }
-
-  Future<void> revoke(String userId) async {
-    await ref.read(localDbProvider).delete(_key(userId));
-    state = AiConsentState(isLoading: false, granted: false, userId: userId);
+  Future<bool> revoke(String userId) async {
+    state = AiConsentState(
+      isLoading: false,
+      isSaving: true,
+      granted: state.granted,
+      userId: userId,
+    );
+    try {
+      await ref.read(localDbProvider).delete(_key(userId));
+      state = AiConsentState(isLoading: false, granted: false, userId: userId);
+      return true;
+    } catch (_) {
+      state = AiConsentState(
+        isLoading: false,
+        granted: true,
+        userId: userId,
+        error: 'Authorization could not be revoked.',
+      );
+      return false;
+    }
   }
 }