Add explicit types and improve type safety across codebase

This commit adds explicit type annotations to variables, function parameters, and return types throughout the codebase, particularly in widget trees, Bloc logic, and repository implementations. The changes improve code readability, maintainability, and type safety, and align with Dart best practices. No business logic was changed.

apps/mobile/apps/design_system_viewer/lib/main.dart

@@ -103,7 +103,7 @@ class _MyHomePageState extends State<MyHomePage> {
           // action in the IDE, or press "p" in the console), to see the
           // wireframe for each widget.
           mainAxisAlignment: .center,
-          children: [
+          children: <Widget>[
             const Text('You have pushed the button this many times:'),
             Text(
               '$_counter',

apps/mobile/apps/staff/lib/main.dart

@@ -17,10 +17,10 @@ void main() async {
 /// The main application module.
 class AppModule extends Module {
   @override
-  List<Module> get imports => [core_localization.LocalizationModule()];
+  List<Module> get imports => <Module>[core_localization.LocalizationModule()];
 
   @override
-  void routes(r) {
+  void routes(RouteManager r) {
     // Set the initial route to the authentication module
     r.module("/", module: staff_authentication.StaffAuthenticationModule());
 
@@ -40,7 +40,7 @@ class AppWidget extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return BlocProvider<core_localization.LocaleBloc>(
-      create: (context) =>
+      create: (BuildContext context) =>
           Modular.get<core_localization.LocaleBloc>()
             ..add(const core_localization.LoadLocale()),
       child:
@@ -48,14 +48,14 @@ class AppWidget extends StatelessWidget {
             core_localization.LocaleBloc,
             core_localization.LocaleState
           >(
-            builder: (context, state) {
+            builder: (BuildContext context, core_localization.LocaleState state) {
               return MaterialApp.router(
                 title: "KROW Staff",
                 theme: UiTheme.light,
                 routerConfig: Modular.routerConfig,
                 locale: state.locale,
                 supportedLocales: state.supportedLocales,
-                localizationsDelegates: const [
+                localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
                   GlobalMaterialLocalizations.delegate,
                   GlobalWidgetsLocalizations.delegate,
                   GlobalCupertinoLocalizations.delegate,