Add persisted local state and baseline CRUD flows

lib/features/signals/signals_controller.dart

@@ -40,9 +40,24 @@ class SignalsController extends AsyncNotifier<SignalsFeed> {
     try {
       return await ref.read(backendGatewayProvider).getSignalsFeed(limit: 20);
     } catch (_) {
-      final List<PersonProfile> people = ref
-          .read(localRepositoryProvider)
-          .people();
+      final LocalDataState localData = await ref.read(
+        localRepositoryProvider.future,
+      );
+      final List<PersonProfile> people = localData.people;
+      final PersonProfile defaultPerson = people.isNotEmpty
+          ? people.first
+          : PersonProfile(
+              id: 'person-default',
+              name: 'Someone Important',
+              relationship: 'Relationship',
+              affinityScore: 70,
+              nextMoment: DateTime(2026, 2, 20),
+              tags: <String>[],
+              notes: '',
+            );
+      final PersonProfile secondaryPerson = people.length > 1
+          ? people[1]
+          : defaultPerson;
       final DateTime now = DateTime.now().toUtc();
       return SignalsFeed(
         cursor: 'fallback-signals',
@@ -50,9 +65,9 @@ class SignalsController extends AsyncNotifier<SignalsFeed> {
           SignalItem(
             id: 'fallback-1',
             type: 'recommendation',
-            title: 'Check in with ${people.first.name} tonight',
+            title: 'Check in with ${defaultPerson.name} tonight',
             description: 'A short voice memo can keep momentum.',
-            personId: people.first.id,
+            personId: defaultPerson.id,
             createdAt: now,
           ),
           SignalItem(
@@ -60,7 +75,7 @@ class SignalsController extends AsyncNotifier<SignalsFeed> {
             type: 'trend',
             title: 'Gift idea: practical + personal is trending',
             description: 'Combine utility with one sentimental detail.',
-            personId: people.last.id,
+            personId: secondaryPerson.id,
             createdAt: now.subtract(const Duration(hours: 2)),
           ),
         ],