feat: Add localization support for contact and SAR marker display names

.claude/settings.local.json

@@ -10,7 +10,8 @@
       "Bash(dart pub global deactivate:*)",
       "Bash(flutter precache:*)",
       "Bash(flutter analyze:*)",
-      "Bash(flutter pub get:*)"
+      "Bash(flutter pub get:*)",
+      "Bash(dart:*)"
     ],
     "deny": [],
     "ask": []

lib/models/contact.dart

@@ -4,6 +4,7 @@ import 'package:latlong2/latlong.dart';
 import 'package:flutter/material.dart';
 import 'contact_telemetry.dart';
 import 'advert_location.dart';
+import '../l10n/app_localizations.dart';
 
 /// MeshCore contact types
 enum ContactType {
@@ -213,6 +214,16 @@ class Contact {
     return advName.substring(emoji.length).trim();
   }
 
+  /// Get localized display name (for Public Channel and other special contacts)
+  String getLocalizedDisplayName(BuildContext context) {
+    // Check if this is the Public Channel (all-zeros public key)
+    if (publicKeyHex == '0000000000000000000000000000000000000000000000000000000000000000') {
+      return AppLocalizations.of(context)!.publicChannel;
+    }
+    // For all other contacts, use the regular display name
+    return displayName;
+  }
+
   /// Check if contact has a learned routing path
   /// When true, messages will use direct routing. When false, messages will use flood mode.
   bool get hasPath => outPathLen > 0 && outPathLen <= 64;

lib/models/sar_marker.dart

@@ -1,5 +1,7 @@
 import 'dart:typed_data';
+import 'package:flutter/material.dart';
 import 'package:latlong2/latlong.dart';
+import '../l10n/app_localizations.dart';
 
 /// SAR (Search & Rescue) marker types
 enum SarMarkerType {
@@ -13,6 +15,23 @@ enum SarMarkerType {
   final String emoji;
   final String displayName;
 
+  /// Get localized display name
+  String getLocalizedName(BuildContext context) {
+    final l10n = AppLocalizations.of(context)!;
+    switch (this) {
+      case SarMarkerType.foundPerson:
+        return l10n.sarMarkerFoundPerson;
+      case SarMarkerType.fire:
+        return l10n.sarMarkerFire;
+      case SarMarkerType.stagingArea:
+        return l10n.sarMarkerStagingArea;
+      case SarMarkerType.object:
+        return l10n.sarMarkerObject;
+      case SarMarkerType.unknown:
+        return 'Unknown';
+    }
+  }
+
   static SarMarkerType fromEmoji(String emoji) {
     switch (emoji) {
       case '🧑':

lib/providers/contacts_provider.dart

@@ -28,8 +28,13 @@ class ContactsProvider with ChangeNotifier {
         excludePublicKey: devicePublicKey,
       );
 
-      // Add stored contacts
+      // Add stored contacts (excluding any with all-zeros public key)
+      const publicChannelKey = '0000000000000000000000000000000000000000000000000000000000000000';
       for (final contact in storedContacts) {
+        // Skip any contacts with all-zeros public key (shouldn't happen, but safety check)
+        if (contact.publicKeyHex == publicChannelKey) {
+          continue;
+        }
         _contacts[contact.publicKeyHex] = contact;
       }
 
@@ -49,7 +54,8 @@ class ContactsProvider with ChangeNotifier {
 
   /// Ensure public channel always exists in the list
   void _ensurePublicChannelExists() {
-    const publicChannelKey = 'public_channel_0';
+    // Public channel has all-zeros public key (32 bytes = 64 hex chars)
+    const publicChannelKey = '0000000000000000000000000000000000000000000000000000000000000000';
     if (!_contacts.containsKey(publicChannelKey)) {
       // Create a pseudo-contact for the public channel (ephemeral broadcast)
       _contacts[publicChannelKey] = Contact(
@@ -70,9 +76,11 @@ class ContactsProvider with ChangeNotifier {
   /// Persist contacts to storage (async, non-blocking)
   Future<void> _persistContacts() async {
     try {
-      // Don't persist the public channel pseudo-contact
+      // Don't persist the public channel pseudo-contact (all zeros key)
-      final contactsToSave = _contacts.values
+      const publicChannelKey = '0000000000000000000000000000000000000000000000000000000000000000';
-          .where((c) => c.publicKeyHex != 'public_channel_0')
+      final contactsToSave = _contacts.entries
+          .where((entry) => entry.key != publicChannelKey)
+          .map((entry) => entry.value)
           .toList();
       await _storageService.saveContacts(contactsToSave);
     } catch (e) {

lib/widgets/map_markers.dart

@@ -172,7 +172,7 @@ class MapMarkers {
                     borderRadius: BorderRadius.circular(3),
                   ),
                   child: Text(
-                    marker.type.displayName,
+                    marker.type.getLocalizedName(context),
                     style: const TextStyle(
                       color: Colors.white,
                       fontSize: 9,
@@ -254,7 +254,7 @@ class MapMarkers {
           children: [
             Text(marker.type.emoji, style: const TextStyle(fontSize: 24)),
             const SizedBox(width: 8),
-            Expanded(child: Text(marker.type.displayName)),
+            Expanded(child: Text(marker.type.getLocalizedName(context))),
           ],
         ),
         content: Column(

lib/widgets/messages/sar_update_sheet.dart

@@ -323,7 +323,7 @@ class _SarUpdateSheetState extends State<SarUpdateSheet> {
                                     const SizedBox(width: 12),
                                     Expanded(
                                       child: Text(
-                                        contact.displayName,
+                                        contact.getLocalizedDisplayName(context),
                                         overflow: TextOverflow.ellipsis,
                                       ),
                                     ),
@@ -764,7 +764,7 @@ class MarkerTypeChip extends StatelessWidget {
             const SizedBox(width: 16),
             Expanded(
               child: Text(
-                type.displayName,
+                type.getLocalizedName(context),
                 style: TextStyle(
                   fontSize: 16,
                   fontWeight: FontWeight.w500,