feat: Centralized Error Handling & Crash Fixes

apps/mobile/packages/features/client/billing/lib/src/presentation/pages/billing_page.dart

@@ -71,13 +71,26 @@ class _BillingViewState extends State<BillingView> {
 
   @override
   Widget build(BuildContext context) {
-    return BlocBuilder<BillingBloc, BillingState>(
+    return BlocConsumer<BillingBloc, BillingState>(
+      listener: (BuildContext context, BillingState state) {
+        if (state.status == BillingStatus.failure && state.errorMessage != null) {
+          UiSnackbar.show(
+            context,
+            message: translateErrorKey(state.errorMessage!),
+            type: UiSnackbarType.error,
+          );
+        }
+      },
       builder: (BuildContext context, BillingState state) {
         return Scaffold(
           body: CustomScrollView(
             controller: _scrollController,
             slivers: <Widget>[
               SliverAppBar(
+                // ... (APP BAR CODE REMAINS UNCHANGED, BUT I MUST INCLUDE IT OR CHUNK IT CORRECTLY)
+                // Since I cannot see the headers in this chunk, I will target the _buildContent method instead
+                // to avoid messing up the whole file structure.
+                // Wait, I can just replace the build method wrapper.
                 pinned: true,
                 expandedHeight: 200.0,
                 backgroundColor: UiColors.primary,
@@ -180,17 +193,28 @@ class _BillingViewState extends State<BillingView> {
     }
 
     if (state.status == BillingStatus.failure) {
-      WidgetsBinding.instance.addPostFrameCallback((_) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(content: Text(translateErrorKey(state.errorMessage!))),
-        );
-      });
-      return Center(
-        child: Text(
-          state.errorMessage != null
-              ? translateErrorKey(state.errorMessage!)
-              : 'An error occurred',
-          style: UiTypography.body1r.textError,
+      return Padding(
+        padding: const EdgeInsets.all(UiConstants.space8),
+        child: Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: <Widget>[
+              const Icon(UiIcons.error, size: 48, color: UiColors.error),
+              const SizedBox(height: UiConstants.space4),
+              Text(
+                state.errorMessage != null
+                    ? translateErrorKey(state.errorMessage!)
+                    : 'An error occurred',
+                style: UiTypography.body1m.textError,
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: UiConstants.space4),
+              UiButton.secondary(
+                text: 'Retry',
+                onPressed: () => BlocProvider.of<BillingBloc>(context).add(const BillingLoadStarted()),
+              ),
+            ],
+          ),
         ),
       );
     }