Add guard for signer in detail screen, add nos.lol additional social relay

lib/models/nostr_adapter.dart

@@ -13,7 +13,12 @@ import 'package:zapstore/widgets/latest_releases_container.dart';
 // NOTE: Very important to use const in relay args to preserve equality in Riverpod families
 // const kAppRelays = {'ws://10.0.2.2:3000'};
 const kAppRelays = {'wss://relay.zapstore.dev'};
-const kSocialRelays = {'wss://relay.damus.io', 'wss://relay.primal.net', 'ndk'};
+const kSocialRelays = {
+  'wss://relay.damus.io',
+  'wss://relay.primal.net',
+  'wss://nos.lol',
+  'ndk'
+};
 const kVertexRelay = {'wss://relay.vertexlab.io'};
 
 mixin NostrAdapter<T extends DataModelMixin<T>> on Adapter<T> {

lib/screens/app_detail_screen.dart

@@ -168,7 +168,9 @@ class AppDetailScreen extends HookConsumerWidget {
                         padding: const EdgeInsets.only(right: 14),
                         child: SignerContainer(app: app),
                       ),
-                      if (app.latestMetadata != null && app.isSelfSigned)
+                      if (app.latestMetadata != null &&
+                          app.signer.isPresent &&
+                          app.isSelfSigned)
                         Column(
                           crossAxisAlignment: CrossAxisAlignment.start,
                           children: [