Improve code clarity and SharedPreferences iteration using .any()

Agent-Logs-Url: https://github.com/openfoodfacts/smooth-app/sessions/55b77ca3-eba4-499e-a998-4ce36355f11d

Co-authored-by: teolemon <1689815+teolemon@users.noreply.github.com>

Author: Copilot

packages/smooth_app/lib/data_models/preferences/user_preferences.dart

@@ -509,16 +509,22 @@ class UserPreferences extends ChangeNotifier {
   ///
   /// This checks both attribute importances (i.e., attributes set to a value
   /// other than "not important") and unwanted ingredients.
+  ///
+  /// The method filters the SharedPreferences key space by the project-specific
+  /// prefix and exits as soon as one configured preference is found.
   bool hasAnyPreferencesForProject(final String projectKey) {
     final String prefix = '${_TAG_PREFIX_IMPORTANCE}${projectKey}_';
-    for (final String key in _sharedPreferences.getKeys()) {
-      if (key.startsWith(prefix)) {
-        final String? value = _sharedPreferences.getString(key);
-        if (value != null &&
-            value != PreferenceImportance.ID_NOT_IMPORTANT) {
-          return true;
+    final bool hasConfiguredAttribute = _sharedPreferences.getKeys().any(
+      (String key) {
+        if (!key.startsWith(prefix)) {
+          return false;
         }
-      }
+        final String? value = _sharedPreferences.getString(key);
+        return value != null && value != PreferenceImportance.ID_NOT_IMPORTANT;
+      },
+    );
+    if (hasConfiguredAttribute) {
+      return true;
     }
     return getUnwantedIngredientsForProject(projectKey).isNotEmpty;
   }

packages/smooth_app/lib/pages/food_preferences/food_preferences_page.dart

@@ -292,6 +292,7 @@ class _FoodPreferencesPageState extends State<FoodPreferencesPage> {
                     ? Colors.white.withValues(alpha: 0.3)
                     : lightTheme
                     ? extension.primaryLight
+                    // Semi-transparent track so the dark header shows through
                     : extension.primarySemiDark.withValues(alpha: 0.5),
                 currentValue: _controller.progress,
                 maxValue: 1,