fix: add context mounted checks for async gaps

lib/features/home/home_page.dart

@@ -25,10 +25,12 @@ class HomePage extends HookConsumerWidget {
 
     useEffect(
       () {
-        Future.delayed(
-          Duration.zero,
-          () async => _getExchanges(context, ref, exchanges),
-        );
+        Future.delayed(Duration.zero, () async {
+          if (context.mounted) {
+            await _getExchanges(context, ref, exchanges);
+          }
+        });
+
         return null;
       },
       [],

lib/features/kcc/kcc_retrieval_page.dart

@@ -28,10 +28,11 @@ class KccRetrievalPage extends HookConsumerWidget {
 
     useEffect(
       () {
-        Future.delayed(
-          Duration.zero,
-          () async => _pollForCredential(context, ref, credential),
-        );
+        Future.delayed(Duration.zero, () async {
+          if (context.mounted) {
+            await _pollForCredential(context, ref, credential);
+          }
+        });
 
         return null;
       },

lib/features/kcc/kcc_webview_page.dart

@@ -43,10 +43,12 @@ class KccWebviewPage extends HookConsumerWidget {
 
     useEffect(
       () {
-        Future.delayed(
-          Duration.zero,
-          () async => _loadWebView(context, ref, idvRequest, webViewController),
-        );
+        Future.delayed(Duration.zero, () async {
+          if (context.mounted) {
+            await _loadWebView(context, ref, idvRequest, webViewController);
+          }
+        });
+
         return null;
       },
       [],

lib/features/payment/payment_amount_page.dart

@@ -44,10 +44,12 @@ class PaymentAmountPage extends HookConsumerWidget {
 
     useEffect(
       () {
-        Future.delayed(
-          Duration.zero,
-          () => _getOfferings(context, ref, dapState?.currencies, offerings),
-        );
+        Future.delayed(Duration.zero, () async {
+          if (context.mounted) {
+            await _getOfferings(context, ref, dapState?.currencies, offerings);
+          }
+        });
+
         return null;
       },
       [],