fix(threads): "Hide Typing & Read Receipts" now governs thread receipts

ThreadPanel only honoured the separate Private Read Receipts switch, so
the privacy switch still emitted public m.read for every opened thread.
Match markAsRead: hideActivity || privateReadReceipts.

Fixes #34

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/room/thread/ThreadPanel.tsx

@@ -116,6 +116,8 @@ export function ThreadPanel({ room, threadId, requestClose }: ThreadPanelProps)
   const editor = useEditor();
   const thread = useThreadInstance(room, threadId);
   const [privateReadReceipts] = useSetting(settingsAtom, 'privateReadReceipts');
+  // "Hide Typing & Read Receipts" must also make thread receipts private (matches markAsRead).
+  const [hideActivity] = useSetting(settingsAtom, 'hideActivity');
   const fileDropContainerRef = useRef<HTMLDivElement>(null) as React.RefObject<HTMLDivElement>;
 
   useKeyDown(
@@ -157,7 +159,7 @@ export function ThreadPanel({ room, threadId, requestClose }: ThreadPanelProps)
       }
       if (!latestId || latestId === lastReadEventIdRef.current) return;
       lastReadEventIdRef.current = latestId;
-      markThreadAsRead(mx, thread, privateReadReceipts).catch(() => {
+      markThreadAsRead(mx, thread, hideActivity || privateReadReceipts).catch(() => {
         // Allow a retry on the next event if the receipt POST failed.
         if (lastReadEventIdRef.current === latestId) {
           lastReadEventIdRef.current = undefined;
@@ -171,7 +173,7 @@ export function ThreadPanel({ room, threadId, requestClose }: ThreadPanelProps)
       thread.off(ThreadEvent.NewReply, markRead);
       thread.off(RoomEvent.Timeline, markRead);
     };
-  }, [mx, thread, privateReadReceipts]);
+  }, [mx, thread, privateReadReceipts, hideActivity]);
 
   return (
     <Box