feat: add thread preview functionality to RoomNavItem component

src/app/features/room-nav/RoomNavItem.tsx

@@ -282,6 +282,20 @@ export function RoomNavItem({
   const roomToParents = useAtomValue(roomToParentsAtom);
   const mDirects = useAtomValue(mDirectAtom);
 
+  // Get first participated thread for preview
+  const firstThreadPreview = (() => {
+    const threads = room.getThreads();
+    const participatedThreads = threads.filter((thread) => thread.hasCurrentUserParticipated);
+    if (participatedThreads.length === 0) return undefined;
+
+    const firstThread = participatedThreads[0];
+    const rootEvent = firstThread.rootEvent;
+    if (!rootEvent) return undefined;
+
+    const rootBody = rootEvent.getContent()?.body ?? '';
+    return rootBody;
+  })();
+
   // Get parent space for DMs
   const parentSpaceInfo = (() => {
     if (!direct || !mDirects.has(room.roomId)) return undefined;
@@ -360,10 +374,15 @@ export function RoomNavItem({
                   />
                 )}
               </Avatar>
-              <Box as="span" grow="Yes">
+              <Box as="span" grow="Yes" direction="Column" style={{ overflow: 'hidden', minWidth: 0 }}>
                 <Text priority={unread ? '500' : '300'} as="span" size="Inherit" truncate>
                   {room.name}
                 </Text>
+                {firstThreadPreview && (
+                  <Text as="span" size="T200" priority="300" truncate>
+                    ╰ {firstThreadPreview}
+                  </Text>
+                )}
               </Box>
               {!optionsVisible && !unread && !selected && typingMember.length > 0 && (
                 <Badge size="300" variant="Secondary" fill="Soft" radii="Pill" outlined>