fix: keep bottom-bar edits ordered to prevent a stale revert

Persisting a bottom-bar edit went through `launchSigner { account.change... }`,
which dispatches on a multi-threaded pool. Because the reactive StateFlow emit
happened inside that coroutine, two quick edits (e.g. tapping Add on several
catalog rows) could complete out of order: the older list would win the flow,
and the settings screen — which re-seeds its editable list from the flow via
`LaunchedEffect(savedItems) { syncFrom(...) }` — would visibly revert the newer
edit and publish the stale list in the NIP-78 event.

Apply the change to the in-memory flow synchronously on the caller (UI) thread
via `Account.applyBottomBarItems` (a non-suspending emit + local save, both
non-blocking) so rapid edits stay strictly ordered, and run only the
sign/encrypt/publish off-thread. Restores the ordering guarantee the previous
synchronous `tryEmit` had.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MJiPHArXZ7P5EvZa7GN9fP

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

@@ -1025,11 +1025,14 @@ class Account(
         }
     }
 
-    suspend fun changeBottomBarItems(items: List<BottomBarEntry>) {
-        if (settings.changeBottomBarItems(items)) {
-            sendNewAppSpecificData()
-        }
-    }
+    /**
+     * Applies the new bottom-bar list to the reactive synced-settings flow and returns whether it
+     * changed. Non-suspending and only touches in-memory state, so callers invoke it synchronously on
+     * the UI thread — rapid edits then stay strictly ordered instead of racing on the multi-threaded
+     * signer dispatcher (an out-of-order write would revert the newer edit, which the settings screen
+     * re-seeds from this flow). Pair a `true` result with [sendNewAppSpecificData] to publish.
+     */
+    fun applyBottomBarItems(items: List<BottomBarEntry>): Boolean = settings.changeBottomBarItems(items)
 
     suspend fun toggleChatroomPin(room: ChatroomKey) {
         settings.toggleChatroomPin(room)
@@ -1082,7 +1085,7 @@ class Account(
         sendNewAppSpecificData()
     }
 
-    private suspend fun sendNewAppSpecificData() = sendMyPublicAndPrivateOutbox(appSpecific.saveNewAppSpecificData())
+    internal suspend fun sendNewAppSpecificData() = sendMyPublicAndPrivateOutbox(appSpecific.saveNewAppSpecificData())
 
     // ---
     // NIP-13 proof-of-work publishing

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/AccountViewModel.kt

@@ -1937,10 +1937,15 @@ class AccountViewModel(
 
     fun bottomBarItemsFlow(): StateFlow<List<BottomBarEntry>> = account.settings.syncedSettings.navigation.bottomBarItems
 
-    fun changeBottomBarItems(items: List<BottomBarEntry>) =
-        launchSigner {
-            account.changeBottomBarItems(items)
+    fun changeBottomBarItems(items: List<BottomBarEntry>) {
+        // Apply to the reactive flow synchronously on the caller (UI) thread so rapid edits stay
+        // ordered — launchSigner dispatches on a multi-threaded pool, so wrapping the emit too would
+        // let two quick edits complete out of order and revert the newer one (the settings screen
+        // re-seeds its editable list from this flow). Only the sign + encrypt + publish runs off-thread.
+        if (account.applyBottomBarItems(items)) {
+            launchSigner { account.sendNewAppSpecificData() }
         }
+    }
 
     fun pinnedChatroomsFlow(): StateFlow<Set<ChatroomKey>> = account.settings.syncedSettings.chats.pinnedChatrooms