Fix request sync duplicate public messages (#707)

Co-authored-by: CC <cc@ggg.local>

app/src/main/java/com/bitchat/android/services/AppStateStore.kt

@@ -13,6 +13,7 @@ import kotlinx.coroutines.flow.asStateFlow
 object AppStateStore {
     // Global de-dup set by message id to avoid duplicate keys in Compose lists
     private val seenMessageIds = mutableSetOf<String>()
+    private val seenPublicMessageKeys = mutableSetOf<String>()
     // Connected peer IDs (mesh ephemeral IDs)
     private val _peers = MutableStateFlow<List<String>>(emptyList())
     val peers: StateFlow<List<String>> = _peers.asStateFlow()
@@ -35,8 +36,10 @@ object AppStateStore {
 
     fun addPublicMessage(msg: BitchatMessage) {
         synchronized(this) {
-            if (seenMessageIds.contains(msg.id)) return
+            val publicKey = publicMessageKey(msg)
+            if (seenMessageIds.contains(msg.id) || seenPublicMessageKeys.contains(publicKey)) return
             seenMessageIds.add(msg.id)
+            seenPublicMessageKeys.add(publicKey)
             _publicMessages.value = _publicMessages.value + msg
         }
     }
@@ -100,10 +103,22 @@ object AppStateStore {
     fun clear() {
         synchronized(this) {
             seenMessageIds.clear()
+            seenPublicMessageKeys.clear()
             _peers.value = emptyList()
             _publicMessages.value = emptyList()
             _privateMessages.value = emptyMap()
             _channelMessages.value = emptyMap()
         }
     }
+
+    private fun publicMessageKey(msg: BitchatMessage): String {
+        val sender = msg.senderPeerID ?: msg.sender
+        return listOf(
+            sender,
+            msg.timestamp.time.toString(),
+            msg.type.name,
+            msg.channel ?: "",
+            msg.content
+        ).joinToString("\u001F")
+    }
 }