V2 Show enterprise demo messages for audit and usage (#5226)

## Summary
- show demo data for audit and usage sections when enterprise licensing
is unavailable
- add enterprise-required banner messaging and reuse demo content
instead of erroring
- update translations for the new enterprise notice

## Testing
- Not run (not requested)


------
[Codex
Task](https://chatgpt.com/codex/tasks/task_b_693af73ad9248328885eb8bb81ccf51a)

frontend/src/core/hooks/useLoginRequired.ts

@@ -1,3 +1,4 @@
+import { useCallback } from 'react';
 import { useAppConfig } from '@app/contexts/AppConfigContext';
 import { alert } from '@app/components/toast';
 import { useTranslation } from 'react-i18next';
@@ -14,30 +15,30 @@ export function useLoginRequired() {
   /**
    * Show alert when user tries to modify settings with login disabled
    */
-  const showLoginRequiredAlert = () => {
+  const showLoginRequiredAlert = useCallback(() => {
     alert({
       alertType: 'warning',
       title: t('admin.error', 'Error'),
       body: t('admin.settings.loginRequired', 'Login mode must be enabled to modify admin settings'),
     });
-  };
+  }, [t]);
 
   /**
    * Validate that login is enabled before allowing action
    * Returns true if login is enabled, false otherwise (and shows alert)
    */
-  const validateLoginEnabled = (): boolean => {
+  const validateLoginEnabled = useCallback((): boolean => {
     if (!loginEnabled) {
       showLoginRequiredAlert();
       return false;
     }
     return true;
-  };
+  }, [loginEnabled, showLoginRequiredAlert]);
 
   /**
    * Wrap an async handler to check login state before executing
    */
-  const withLoginCheck = <T extends (...args: any[]) => Promise<any>>(
+  const withLoginCheck = useCallback(<T extends (...args: any[]) => Promise<any>>(
     handler: T
   ): T => {
     return (async (...args: any[]) => {
@@ -46,12 +47,12 @@ export function useLoginRequired() {
       }
       return handler(...args);
     }) as T;
-  };
+  }, [validateLoginEnabled]);
 
   /**
    * Get styles for disabled inputs (cursor not-allowed)
    */
-  const getDisabledStyles = () => {
+  const getDisabledStyles = useCallback(() => {
     if (!loginEnabled) {
       return {
         input: { cursor: 'not-allowed' },
@@ -60,12 +61,12 @@ export function useLoginRequired() {
       };
     }
     return undefined;
-  };
+  }, [loginEnabled]);
 
   /**
    * Wrap fetch function to skip API call when login disabled
    */
-  const withLoginCheckForFetch = <T extends (...args: any[]) => Promise<any>>(
+  const withLoginCheckForFetch = useCallback(<T extends (...args: any[]) => Promise<any>>(
     fetchHandler: T,
     skipWhenDisabled: boolean = true
   ): T => {
@@ -76,7 +77,7 @@ export function useLoginRequired() {
       }
       return fetchHandler(...args);
     }) as T;
-  };
+  }, [loginEnabled]);
 
   return {
     loginEnabled,