Added tab visibility context and provider for dynamic tab management

- Introduced TabVisibilityProvider component
- Created TabContent for conditional rendering
- Added context and hooks for tab visibility
- Updated DocumentManager dependencies
- Integrated provider in App component

lightrag_webui/src/components/ui/TabContent.tsx

@@ -0,0 +1,39 @@
+import React, { useEffect } from 'react';
+import { useTabVisibility } from '@/contexts/useTabVisibility';
+
+interface TabContentProps {
+  tabId: string;
+  children: React.ReactNode;
+  className?: string;
+}
+
+/**
+ * TabContent component that manages visibility based on tab selection
+ * Works with the TabVisibilityContext to show/hide content based on active tab
+ */
+const TabContent: React.FC<TabContentProps> = ({ tabId, children, className = '' }) => {
+  const { isTabVisible, setTabVisibility } = useTabVisibility();
+  const isVisible = isTabVisible(tabId);
+
+  // Register this tab with the context when mounted
+  useEffect(() => {
+    setTabVisibility(tabId, true);
+    
+    // Cleanup when unmounted
+    return () => {
+      setTabVisibility(tabId, false);
+    };
+  }, [tabId, setTabVisibility]);
+
+  if (!isVisible) {
+    return null;
+  }
+
+  return (
+    <div className={className}>
+      {children}
+    </div>
+  );
+};
+
+export default TabContent;