added code from unity

Runtime/UI/PopupTrigger.cs

@@ -0,0 +1,48 @@
+using UnityEngine;
+using UnityEngine.EventSystems;
+
+namespace Jovian.PopupSystem.UI {
+    /// <summary>
+    /// Reference holder MonoBehaviour for popup triggers. Attach to any UI element with a
+    /// Graphic component (Image, TMP_Text, etc.) that has Raycast Target enabled.
+    /// Configure category, anchor side, and position mode in the Inspector.
+    /// Forwards pointer events to the bound <see cref="PopupTriggerView"/>.
+    /// </summary>
+    public class PopupTrigger : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler {
+        [SerializeField] PopupCategory category;
+        [SerializeField] AnchorSide anchorSide = AnchorSide.Below;
+        [SerializeField] PopupPositionMode positionMode = PopupPositionMode.AnchorToElement;
+
+        PopupTriggerView handler;
+
+        /// <summary>The popup category this trigger belongs to.</summary>
+        public PopupCategory Category => category;
+
+        /// <summary>Which side of this element the popup anchors to.</summary>
+        public AnchorSide AnchorSide => anchorSide;
+
+        /// <summary>Whether the popup anchors to this element or follows the mouse.</summary>
+        public PopupPositionMode PositionMode => positionMode;
+
+        /// <summary>The bound behavior handler. Null until <see cref="Bind"/> is called.</summary>
+        public PopupTriggerView Handler => handler;
+
+        /// <summary>
+        /// Binds a <see cref="PopupTriggerView"/> to this trigger. Called automatically
+        /// by <see cref="IPopupSystem.ScanTriggers"/> or <see cref="IPopupSystem.InitializeTriggersInChildren"/>.
+        /// </summary>
+        public void Bind(PopupTriggerView view) {
+            handler = view;
+        }
+
+        /// <summary>Forwards pointer enter to the bound handler.</summary>
+        public void OnPointerEnter(PointerEventData eventData) {
+            handler?.OnPointerEnter(this);
+        }
+
+        /// <summary>Forwards pointer exit to the bound handler.</summary>
+        public void OnPointerExit(PointerEventData eventData) {
+            handler?.OnPointerExit(this);
+        }
+    }
+}