Desktop/remove hard requirement auth wall on desktop (#5956)

Co-authored-by: Claude Sonnet 4.6 <[email protected]>

frontend/src/core/tools/AddAttachments.tsx

@@ -90,7 +90,8 @@ const AddAttachments = ({ onPreviewFile, onComplete, onError }: BaseToolProps) =
       isVisible: !hasResults,
       loadingText: t('loading'),
       onClick: handleExecute,
-      disabled: !params.validateParameters() || !hasFiles || !endpointEnabled,
+      endpointEnabled: endpointEnabled,
+      paramsValid: params.validateParameters(),
     },
     review: {
       isVisible: hasResults,