android: add realtime foreground local notifications with active chat gating

android/app/src/test/java/ru/daemonlord/messenger/data/chat/repository/NetworkChatRepositoryTest.kt

@@ -137,6 +137,10 @@ class NetworkChatRepositoryTest {
             return chats.map { entities -> entities.firstOrNull { it.id == chatId }?.toLocalModel() }
         }
 
+        override suspend fun getChatDisplayTitle(chatId: Long): String? {
+            return chats.value.firstOrNull { it.id == chatId }?.displayTitle
+        }
+
         override suspend fun upsertChats(chats: List<ChatEntity>) {
             val merged = this.chats.value.associateBy { it.id }.toMutableMap()
             chats.forEach { merged[it.id] = it }