fix(sync): board-card rollback, inbox status sync, markRead error handling

- board-card: capture prev issue before optimistic update, restore on error
- useRealtimeSync: wire issue:updated WS handler to update inbox issue_status
- inbox: markRead uses optimistic update, refetch on error with toast

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/features/issues/components/board-card.tsx

@@ -47,12 +47,14 @@ export const BoardCardContent = memo(function BoardCardContent({
 
   const handleUpdate = useCallback(
     (updates: Partial<UpdateIssueRequest>) => {
+      const prev = { ...issue };
       useIssueStore.getState().updateIssue(issue.id, updates);
       api.updateIssue(issue.id, updates).catch(() => {
+        useIssueStore.getState().updateIssue(issue.id, prev);
         toast.error("Failed to update issue");
       });
     },
-    [issue.id]
+    [issue],
   );
 
   const showPriority = storeProperties.priority;