Fix resize handler: use ref to avoid stale closure and listener churn

Register resize listener once with empty deps; track left via ref so
the debounced callback always reads the current offset without
re-registering on every click.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/modules/custom/riverside_pt/js/components/rpt-testimonials.js

@@ -1,5 +1,5 @@
 import { h, render } from "https://esm.sh/preact@10";
-import { useState, useRef } from "https://esm.sh/preact@10/hooks";
+import { useState, useEffect, useRef } from "https://esm.sh/preact@10/hooks";
 import { html } from "https://esm.sh/htm@3/preact";
 
 const TESTIMONIALS = [
@@ -54,6 +54,27 @@ function Testimonials() {
     setLeft(function (l) { return Math.max(-maxL, l - STEP); });
   };
 
+  var leftRef = useRef(left);
+  leftRef.current = left;
+
+  useEffect(function () {
+    var timer;
+    function onResize() {
+      clearTimeout(timer);
+      timer = setTimeout(function () {
+        var max = measureMax();
+        if (-leftRef.current > max) {
+          setLeft(-max);
+        }
+      }, 150);
+    }
+    window.addEventListener("resize", onResize);
+    return function () {
+      clearTimeout(timer);
+      window.removeEventListener("resize", onResize);
+    };
+  }, []);
+
   var atStart = left >= 0;
 
   return html`