fix: persist MLS chat unread state across app restarts

The unread dot for Marmot/MLS group rooms was driven by an in-memory
unreadCount on MarmotGroupChatroom. On restart the MLS group state is
restored from the last persisted commit, the kind:445 subscription
restarts with since=null, and the in-memory processed-event dedup set is
empty — so relays redeliver old group events, they re-decrypt as fresh
application messages, and the counter was re-bumped, resurrecting the
dot for chats already read.

Marking-as-read was already persisted: opening a group chat writes the
newest rendered message's createdAt to the MarmotGroup/<groupId> route
in lastReadPerRoute (saved to disk with account settings). Compute the
unread indicators from that timestamp instead — exactly how DM rooms
and public channels do it — in both the Messages screen row and the
Marmot group list row.

With no consumer left, drop the volatile counter and collapse the
addMessageSync/restoreMessageSync split (they only differed in the
counter bump).

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -3549,7 +3549,7 @@ class Account(
                                 if (isNew) {
                                     innerNote.event = innerEvent
                                 }
-                                marmotGroupList.restoreMessage(groupId, innerNote)
+                                marmotGroupList.addMessage(groupId, innerNote)
                             } catch (e: Exception) {
                                 Log.w(
                                     "Account",

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupChatView.kt

@@ -100,11 +100,6 @@ fun MarmotGroupChatView(
     newMessageModel.init(accountViewModel)
     newMessageModel.load(nostrGroupId)
 
-    DisposableEffect(nostrGroupId) {
-        newMessageModel.chatroom?.markAsRead()
-        onDispose { }
-    }
-
     // Resolve the navigation-supplied replyId (e.g. tapping reply on an MLS
     // message in the Notifications screen) into the actual Note once it has
     // landed in LocalCache. checkGetOrCreateNote is a no-op for unknown ids.

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupListScreen.kt

@@ -222,11 +222,16 @@ fun MarmotGroupListItem(
     onClick: () -> Unit,
 ) {
     val displayName by chatroom.displayName.collectAsStateWithLifecycle()
-    val unread by chatroom.unreadCount.collectAsStateWithLifecycle()
     val members by chatroom.members.collectAsStateWithLifecycle()
     val memberPubkeys = remember(members) { members.map { it.pubkey } }
     val newestMessage = chatroom.newestMessage
 
+    val lastReadTime by accountViewModel.account.loadLastReadFlow("MarmotGroup/$groupId").collectAsStateWithLifecycle()
+    val unread =
+        remember(newestMessage, lastReadTime) {
+            chatroom.messages.count { (it.createdAt() ?: Long.MIN_VALUE) > lastReadTime }
+        }
+
     Row(
         modifier =
             Modifier

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/rooms/ChatroomHeaderCompose.kt

@@ -260,7 +260,6 @@ private fun MarmotGroupRoomCompose(
     nav: INav,
 ) {
     val displayName by chatroom.displayName.collectAsStateWithLifecycle()
-    val unread by chatroom.unreadCount.collectAsStateWithLifecycle()
 
     val author = lastMessage.author
     val noteEvent = lastMessage.event
@@ -274,13 +273,15 @@ private fun MarmotGroupRoomCompose(
             stringRes(R.string.marmot_group_no_messages_yet)
         }
 
+    val lastReadTime by accountViewModel.account.loadLastReadFlow("MarmotGroup/${chatroom.nostrGroupId}").collectAsStateWithLifecycle()
+
     ChannelName(
         channelIdHex = chatroom.nostrGroupId,
         channelPicture = null,
         channelTitle = { modifier -> ChannelTitleWithLabelInfo(groupName, R.string.marmot_group, modifier) },
         channelLastTime = lastMessage.createdAt(),
         channelLastContent = lastContent,
-        hasNewMessages = unread > 0,
+        hasNewMessages = (lastMessage.createdAt() ?: Long.MIN_VALUE) > lastReadTime,
         loadProfilePicture = accountViewModel.settings.showProfilePictures(),
         loadRobohash = accountViewModel.settings.isNotPerformanceMode(),
         autoPlayGif =

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/marmotGroups/MarmotGroupChatroom.kt

@@ -53,7 +53,6 @@ class MarmotGroupChatroom(
     var memberCount = MutableStateFlow(0)
     var members = MutableStateFlow<List<GroupMemberInfo>>(emptyList())
     var newestMessage: Note? = null
-    val unreadCount = MutableStateFlow(0)
 
     /**
      * Tracks the most recent createdAt (seconds) of a kind:445 group event
@@ -125,30 +124,6 @@ class MarmotGroupChatroom(
     }
 
     fun addMessageSync(msg: Note): Boolean =
-        syncLock.withLock {
-            if (msg !in messages) {
-                messages = messages + msg
-                msg.addGatherer(this)
-
-                val createdAt = msg.createdAt() ?: 0L
-                if (createdAt > (newestMessage?.createdAt() ?: 0L)) {
-                    newestMessage = msg
-                }
-
-                unreadCount.value += 1
-                changesFlow?.get()?.tryEmit(ListChange.Addition(msg))
-                return@withLock true
-            }
-            return@withLock false
-        }
-
-    /**
-     * Add a message that is being restored from persistent storage on app
-     * startup. Behaves like [addMessageSync] but does NOT bump the unread
-     * count — restored messages were already seen by the user in a previous
-     * session.
-     */
-    fun restoreMessageSync(msg: Note): Boolean =
         syncLock.withLock {
             if (msg !in messages) {
                 messages = messages + msg
@@ -181,10 +156,6 @@ class MarmotGroupChatroom(
             return@withLock false
         }
 
-    fun markAsRead() {
-        unreadCount.value = 0
-    }
-
     fun recordRelayActivity(
         relay: NormalizedRelayUrl,
         createdAt: Long,
@@ -220,7 +191,6 @@ class MarmotGroupChatroom(
             if (toRemove.isEmpty()) return@withLock toRemove
             messages = emptySet()
             newestMessage = null
-            unreadCount.value = 0
             changesFlow?.get()?.tryEmit(ListChange.SetDeletion<Note>(toRemove))
             toRemove
         }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/marmotGroups/MarmotGroupList.kt

@@ -49,35 +49,7 @@ class MarmotGroupList(
     ) {
         if (!isDisplayableFeedMessage(msg)) return
         val chatroom = getOrCreateGroup(nostrGroupId)
-        val isSelfAuthored = msg.author?.pubkeyHex == ownerPubKey
-        // Use the quiet path for our own messages so the relay round-trip
-        // doesn't mark the user's own outgoing message as unread.
-        val added =
-            if (isSelfAuthored) {
-                chatroom.restoreMessageSync(msg)
-            } else {
-                chatroom.addMessageSync(msg)
-            }
-        if (added) {
-            noteToGroupIndex.getOrCreate(msg.idHex) { nostrGroupId }
-            if (isSelfAuthored) {
-                chatroom.ownerSentMessage = true
-            }
-            _groupListChanges.tryEmit(nostrGroupId)
-        }
-    }
-
-    /**
-     * Add a message that was restored from persistent storage at app startup.
-     * Does not bump the chatroom's unread counter.
-     */
-    fun restoreMessage(
-        nostrGroupId: HexKey,
-        msg: Note,
-    ) {
-        if (!isDisplayableFeedMessage(msg)) return
-        val chatroom = getOrCreateGroup(nostrGroupId)
-        if (chatroom.restoreMessageSync(msg)) {
+        if (chatroom.addMessageSync(msg)) {
             noteToGroupIndex.getOrCreate(msg.idHex) { nostrGroupId }
             if (msg.author?.pubkeyHex == ownerPubKey) {
                 chatroom.ownerSentMessage = true