fix(notifications): anchor the push prefetch at the unread boundary

The catch-up triggered by a push notification fetched the newest page
for rooms without any cached chat block, so a large unread backlog left
a chat block floating above the unread boundary — the same window shape
that misplaces the unread marker on chat open.

Look up the pushed room in the local conversations cache and pass its
lastReadMessage and unread count to catchUpRoom, so the initial fetch
is anchored at the boundary when the backlog calls for it. The boundary
is room-level state and therefore not passed for thread catch-ups.

Assisted-by: Claude Code:claude-fable-5
Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

Author: AndyScherzinger

app/src/main/java/com/nextcloud/talk/jobs/ChatMessageCatchUpWorker.kt

@@ -22,11 +22,13 @@ import autodagger.AutoInjector
 import com.nextcloud.talk.application.NextcloudTalkApplication
 import com.nextcloud.talk.application.NextcloudTalkApplication.Companion.sharedApplication
 import com.nextcloud.talk.chat.data.network.ChatMessageSyncer
+import com.nextcloud.talk.data.database.dao.ConversationsDao
 import com.nextcloud.talk.users.UserManager
 import com.nextcloud.talk.utils.ApiUtils
 import com.nextcloud.talk.utils.bundle.BundleKeys.KEY_INTERNAL_USER_ID
 import com.nextcloud.talk.utils.bundle.BundleKeys.KEY_ROOM_TOKEN
 import com.nextcloud.talk.utils.bundle.BundleKeys.KEY_THREAD_ID
+import kotlinx.coroutines.flow.first
 import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
@@ -51,6 +53,9 @@ class ChatMessageCatchUpWorker(context: Context, workerParams: WorkerParameters)
     @Inject
     lateinit var chatMessageSyncer: ChatMessageSyncer
 
+    @Inject
+    lateinit var conversationsDao: ConversationsDao
+
     override suspend fun doWork(): Result {
         sharedApplication!!.componentApplication.inject(this)
 
@@ -89,7 +94,23 @@ class ChatMessageCatchUpWorker(context: Context, workerParams: WorkerParameters)
             urlForChatting = ApiUtils.getUrlForChat(CHAT_API_VERSION, user.baseUrl!!, roomToken)
         )
 
-        val outcome = runCatching { chatMessageSyncer.catchUpRoom(target) }.getOrElse { throwable ->
+        // For a room without any cached chat block the unread boundary of the locally cached
+        // conversation is passed along, so a large backlog is fetched anchored at the last read
+        // message and the unread marker can be placed when the chat is opened. The boundary is
+        // room-level state and therefore not passed for thread catch-ups.
+        val conversation = if (threadId == null) {
+            conversationsDao.getConversationForUser(user.id!!, roomToken).first()
+        } else {
+            null
+        }
+
+        val outcome = runCatching {
+            chatMessageSyncer.catchUpRoom(
+                target = target,
+                lastReadMessage = conversation?.lastReadMessage,
+                unreadMessages = conversation?.unreadMessages ?: 0
+            )
+        }.getOrElse { throwable ->
             Log.e(TAG, "Message catch-up failed for room $roomToken", throwable)
             null
         }