consistent message spacing

src/chat/components/MessageItem.svelte

@@ -369,14 +369,14 @@
   {/if}
 
   <div class="message-content">
-    <div class="message-header">
-      {#if !isGrouped}
+    {#if !isGrouped}
+      <div class="message-header">
         <span class="user-name" onclick={() => (chat.viewingProfileUser = chat.users.find(u => u.identity.isEqual(msg.sender)) || null)} style="cursor: pointer;">{msgUsername}</span>
         {#if !isThread}
           <span class="message-time">{chat.formatTime(msg.sent)}</span>
         {/if}
-      {/if}
-    </div>
+      </div>
+    {/if}
 
     <div class="message-text">
       {#if isEditing}
@@ -508,15 +508,14 @@
 
 <style>
   .message-item {
-    padding: 8px 16px;
+    padding: 4px 16px;
     display: flex;
     gap: 16px;
     position: relative;
   }
 
-  .message-item.grouped {
-    padding-top: 4px;
-    padding-bottom: 4px;
+  .message-item:not(.grouped) {
+    padding-top: 12px;
   }
 
   .message-item:hover {