fix: Concord unread badge + last-message previews ignore thread replies

The unread count, the channel-list/hub last-message previews, and the
Messages-row summary all read a broader note set than the channel feed
renders: the feed's ChannelFeedFilter hides kind-1111 CommentEvent thread
replies (and unacceptable authors), but these row surfaces counted/showed
them. A trailing minichat reply therefore stuck the unread badge at a count
opening the channel could never clear (markAsRead is monotonic and only
advances for rendered timeline messages), and showed up as a "last message"
that isn't on the timeline.

Centralizes the feed's predicate as isConcordTimelineMessage (loaded,
acceptable, not a CommentEvent) plus a newestTimelineNote helper, and routes
the unread count, both list-row previews, and the Messages hub filter through
it — so every channel-row summary agrees with what the open channel renders.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/concord/ConcordChannelListScreen.kt

@@ -338,7 +338,9 @@ private fun ConcordChannelListRow(
         .flow()
         .notes.stateFlow
         .collectAsStateWithLifecycle()
-    val lastNote = channelState.channel.lastNote
+    // The newest *timeline* message (not the raw lastNote): skips kind-1111 thread replies and
+    // hidden authors so the preview + time match the channel feed and the unread badge below.
+    val lastNote = remember(channelState) { channel.newestTimelineNote(account) }
     val unread by
         remember(communityId, channelKey) { concordChannelUnreadCountFlow(account, communityId, channelKey) }
             .collectAsStateWithLifecycle(0)

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/concord/ConcordHomeScreen.kt

@@ -402,7 +402,9 @@ private fun ConcordChannelRow(
         .flow()
         .notes.stateFlow
         .collectAsStateWithLifecycle()
-    val lastNote = channelState.channel.lastNote
+    // The newest *timeline* message (not the raw lastNote): skips kind-1111 thread replies and
+    // hidden authors so the preview + time match the channel feed and the unread badge below.
+    val lastNote = remember(channelState) { channel.newestTimelineNote(account) }
     val unreadCount by
         remember(communityId, channelKey) { concordChannelUnreadCountFlow(account, communityId, channelKey) }
             .collectAsStateWithLifecycle(0)

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/concord/ConcordUnread.kt

@@ -20,11 +20,14 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.concord
 
+import com.vitorpamplona.amethyst.commons.model.Channel
 import com.vitorpamplona.amethyst.commons.model.concord.ConcordChannel
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.quartz.concord.cord03Channels.ConcordChannelId
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip22Comments.CommentEvent
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
 
@@ -51,12 +54,48 @@ fun concordChannelUnreadCountFlow(
         account.loadLastReadFlow(concordChannelLastReadRoute(communityId, channelKey)),
         channel.flow().notes.stateFlow,
     ) { lastRead, _ ->
-        channel.newMessagesSince(lastRead)
+        channel.newMessagesSince(account, lastRead)
     }
 }
 
-/** The number of this channel's messages created strictly after [sinceSecs] (0 if none). */
-private fun ConcordChannel.newMessagesSince(sinceSecs: Long): Int = notes.count { _, note -> (note.createdAt() ?: 0L) > sinceSecs }
+/**
+ * True for a note the Concord channel *timeline* actually renders — the same predicate as
+ * [com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.dal.ChannelFeedFilter]'s
+ * `isTimelineMessage`: a loaded, acceptable message that is **not** a kind-1111 [CommentEvent].
+ *
+ * A [CommentEvent] is a *minichat thread reply* that lives inside its parent's thread, not on the
+ * flat timeline, so it never composes on the channel screen and never advances the last-read
+ * marker. Every list-row surface that summarizes a channel — the unread badge
+ * ([newMessagesSince]), the last-message preview + timestamp ([newestTimelineNote]), and the
+ * Messages hub row — reuses this so none of them can disagree with the open channel's feed:
+ * a trailing comment can't stick the badge at a count the user can never clear, nor show up as a
+ * "last message" that isn't in the timeline. Unacceptable (muted/blocked) authors are hidden for
+ * the same reason.
+ */
+fun isConcordTimelineMessage(
+    note: Note,
+    account: Account,
+): Boolean = note.event.let { it != null && it !is CommentEvent } && account.isAcceptable(note)
+
+/**
+ * The newest timeline message in this channel (see [isConcordTimelineMessage]), or null if none —
+ * the note the list/hub rows show as the channel's "last message". Unlike [ConcordChannel.lastNote]
+ * (the raw newest note of any kind), this skips thread replies and hidden authors so the preview
+ * matches what the channel feed renders and the unread badge counts.
+ */
+fun ConcordChannel.newestTimelineNote(account: Account): Note? =
+    notes
+        .filter { _, note -> isConcordTimelineMessage(note, account) }
+        .minWithOrNull(Channel.DefaultFeedOrder)
+
+/** The number of this channel's timeline messages created strictly after [sinceSecs] (0 if none). */
+private fun ConcordChannel.newMessagesSince(
+    account: Account,
+    sinceSecs: Long,
+): Int =
+    notes.count { _, note ->
+        (note.createdAt() ?: 0L) > sinceSecs && isConcordTimelineMessage(note, account)
+    }
 
 /**
  * The pubkeys of the [limit] most-recent distinct posters in this channel, newest first — the

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

@@ -30,6 +30,7 @@ import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.dal.AdditiveFeedFilter
 import com.vitorpamplona.amethyst.ui.dal.sortedByDefaultFeedOrder
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.concord.isConcordTimelineMessage
 import com.vitorpamplona.quartz.concord.cord03Channels.ConcordChannelId
 import com.vitorpamplona.quartz.experimental.ephemChat.chat.EphemeralChatEvent
 import com.vitorpamplona.quartz.experimental.ephemChat.chat.RoomId
@@ -400,10 +401,15 @@ class ChatroomListKnownFeedFilter(
             .sortedByDefaultFeedOrder()
             .firstOrNull()
 
-    /** The newest decrypted message loaded in this Concord channel, or null if none yet. */
+    /**
+     * The newest decrypted *timeline* message loaded in this Concord channel, or null if none yet.
+     * Uses [isConcordTimelineMessage] so a trailing kind-1111 thread reply (or a hidden author)
+     * isn't shown as the Messages-row "last message" — the same predicate the channel feed and the
+     * unread badge use, so the row summary can't disagree with what opening the channel renders.
+     */
     private fun ConcordChannel.newestConcordNote(account: Account): Note? =
         notes
-            .filter { _, it -> account.isAcceptable(it) && it.event != null }
+            .filter { _, it -> isConcordTimelineMessage(it, account) }
             .sortedByDefaultFeedOrder()
             .firstOrNull()