fix(marmot): don't mark own messages unread + pad empty group list

- `MarmotGroupList.addMessage` now routes self-authored messages
  through `restoreMessageSync` (the no-unread-bump path) so the
  relay round-trip of a message the user just sent doesn't show up
  as an unread bold entry in the group list and doesn't bump the
  unread badge counter.
- `MarmotGroupListScreen` empty state now has 32dp horizontal
  padding and centered text alignment so the "No invitations" /
  "No groups yet" copy doesn't run into the screen edges.

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

@@ -148,13 +148,17 @@ fun MarmotGroupListScreen(
 
             if (visibleGroups.isEmpty()) {
                 Box(
-                    modifier = Modifier.fillMaxSize(),
+                    modifier =
+                        Modifier
+                            .fillMaxSize()
+                            .padding(horizontal = 32.dp),
                     contentAlignment = Alignment.Center,
                 ) {
                     Column(horizontalAlignment = Alignment.CenterHorizontally) {
                         Text(
                             text = if (selectedTab == 0) "No groups yet" else "No invitations",
                             style = MaterialTheme.typography.titleMedium,
+                            textAlign = TextAlign.Center,
                         )
                         Text(
                             text =
@@ -165,6 +169,7 @@ fun MarmotGroupListScreen(
                                 },
                             style = MaterialTheme.typography.bodyMedium,
                             color = MaterialTheme.colorScheme.onSurfaceVariant,
+                            textAlign = TextAlign.Center,
                             modifier = Modifier.padding(top = 4.dp),
                         )
                     }

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

@@ -46,8 +46,17 @@ class MarmotGroupList(
         msg: Note,
     ) {
         val chatroom = getOrCreateGroup(nostrGroupId)
-        if (chatroom.addMessageSync(msg)) {
+        val isSelfAuthored = msg.author?.pubkeyHex == ownerPubKey
-            if (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) {
+            if (isSelfAuthored) {
                 chatroom.ownerSentMessage = true
             }
             _groupListChanges.tryEmit(nostrGroupId)