fix(ui): resolve multi-line border issue in permission notification cards

- Removed box-shadow from active permission items to eliminate double-border effect
- Added CSS rule to remove borders from nested ToolCall components within permission items
- Ensures consistent single-border styling aligned with existing design system

packages/ui/src/styles/components/permission-notification.css

@@ -139,7 +139,6 @@
 
 .permission-center-item-active {
   border-color: var(--session-status-permission-fg);
-  box-shadow: 0 0 0 1px color-mix(in srgb, var(--session-status-permission-fg) 35%, transparent);
 }
 
 .permission-center-item-header {
@@ -217,6 +216,13 @@
   font-size: var(--font-size-sm);
 }
 
+/* Remove border from tool-call when inside permission items to avoid double borders */
+.permission-center-item .tool-call {
+  border: none;
+  border-radius: 0;
+  margin: 0;
+}
+
 @media (max-width: 720px) {
   .permission-center-modal-backdrop {
     padding: 0;
@@ -228,4 +234,4 @@
     max-height: none;
     border-radius: 0;
   }
-}
+}