feat: Favourites support using firmware flags bit 0

- Contact.isFavourite reads bit 0 of firmware flags field
- Toggle favourite via contact action sheet (writes to device)
- Favourites section shown first in contacts tab
- Path size options corrected to [1, 2, 3] bytes

lib/providers/contacts_provider.dart

@@ -342,6 +342,8 @@ class ContactsProvider with ChangeNotifier {
   }
 
   List<Contact> get contacts => _contacts.values.toList();
+  List<Contact> get favouriteContacts =>
+      _contacts.values.where((c) => c.isFavourite).toList();
   List<SavedContactGroup> get savedContactGroups =>
       List<SavedContactGroup>.from(_savedContactGroups)
         ..sort((a, b) => b.createdAt.compareTo(a.createdAt));

lib/screens/contacts_tab.dart

@@ -688,6 +688,19 @@ class _ContactsTabState extends State<ContactsTab> {
             child: ListView(
               padding: const EdgeInsets.all(8),
               children: [
+                // Favourites (contacts with firmware favourite flag set)
+                if (contactsProvider.favouriteContacts.isNotEmpty) ...[
+                  _SectionHeader(
+                    title: 'Favourites',
+                    count: contactsProvider.favouriteContacts.length,
+                    icon: Icons.star,
+                  ),
+                  ..._buildContactSectionItems(
+                    contactsProvider.favouriteContacts,
+                  ),
+                  const Divider(height: 32),
+                ],
+
                 // Team Members (Chat contacts)
                 if (showTeamMembersSection) ...[
                   _SectionHeader(

lib/services/contact_storage_service.dart

@@ -210,6 +210,38 @@ class ContactStorageService {
     }
   }
 
+  // ── Favorites ───────────────────────────────────────────────────────────────
+
+  static const String _favoritesKey = 'contact_favorites';
+
+  Future<void> saveFavorites(
+    Set<String> publicKeyHexes, {
+    String? namespace,
+  }) async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      await prefs.setStringList(
+        _key(_favoritesKey, namespace: namespace),
+        publicKeyHexes.toList(),
+      );
+    } catch (e) {
+      debugPrint('❌ [ContactStorage] Error saving favorites: $e');
+    }
+  }
+
+  Future<Set<String>> loadFavorites({String? namespace}) async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final list = prefs.getStringList(
+        _key(_favoritesKey, namespace: namespace),
+      );
+      return list?.toSet() ?? {};
+    } catch (e) {
+      debugPrint('❌ [ContactStorage] Error loading favorites: $e');
+      return {};
+    }
+  }
+
   /// Get storage statistics
   Future<Map<String, dynamic>> getStorageStats({String? namespace}) async {
     try {

lib/services/route_hash_preferences.dart

@@ -25,8 +25,7 @@ class RouteHashPreferences {
 
   /// Valid hash sizes per the MeshCore protocol.
   /// The path encoding uses 2 bits: 00=1B, 01=2B, 10=3B, 11=4B.
-  /// The official app offers 1, 2, 4 (skipping 3).
-  static const List<int> supportedSizes = [1, 2, 4];
+  static const List<int> supportedSizes = [1, 2, 3];
 
   static int _normalize(int value) {
     if (supportedSizes.contains(value)) return value;

lib/widgets/contacts/contact_tile.dart

@@ -348,6 +348,29 @@ class ContactTile extends StatelessWidget {
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
+              if (!contact.isChannel)
+                ListTile(
+                  leading: Icon(
+                    contact.isFavourite ? Icons.star : Icons.star_outline,
+                    color: contact.isFavourite ? Colors.amber : null,
+                  ),
+                  title: Text(
+                    contact.isFavourite
+                        ? 'Remove from Favourites'
+                        : 'Add to Favourites',
+                  ),
+                  onTap: () async {
+                    Navigator.pop(sheetContext);
+                    final toggled = contact.toggleFavourite();
+                    final connectionProvider =
+                        context.read<ConnectionProvider>();
+                    await connectionProvider.addOrUpdateContact(toggled);
+                    if (context.mounted) {
+                      // Refresh contact from device so the local cache is updated
+                      await connectionProvider.getContact(contact.publicKey);
+                    }
+                  },
+                ),
               ListTile(
                 leading: const Icon(Icons.message_outlined),
                 title: Text(l10n.messages),