feat: web UI chat render, panels, presence + analytics

frontend/src/lib/components/ChatList.svelte

@@ -25,6 +25,8 @@
       : chats.list.filter((chat) => folderContains(selectedFolder, chat))
   );
 
+  const SCROLL_THRESHOLD = 600;
+
   $effect(() => {
     if (accounts.selectedId === null) {
       return;
@@ -32,9 +34,16 @@
     chats.load().catch(() => toasts.error("Failed to load chats"));
     folders.load().catch(() => toasts.error("Failed to load folders"));
   });
+
+  function onScroll(event: Event) {
+    const el = event.currentTarget as HTMLElement;
+    if (el.scrollTop + el.clientHeight >= el.scrollHeight - SCROLL_THRESHOLD) {
+      chats.loadMore().catch(() => undefined);
+    }
+  }
 </script>
 
-<div class="chat-list custom-scroll">
+<div class="chat-list custom-scroll" onscroll={onScroll}>
   {#if chats.loading && chats.list.length === 0}
     {#each skeletonRows as index (index)}
       <div class="row-skeleton">
@@ -53,7 +62,7 @@
         class="folder-view"
         in:fly={{ x: folders.direction * 24, duration: 200, easing: cubicOut }}
       >
-        {#if visibleChats.length === 0}
+        {#if visibleChats.length === 0 && !chats.hasMore}
           <EmptyState
             title="Empty folder"
             description="No chats match this folder yet"