fix(modals): ConfirmModal locks body scroll + respects loading on backdrop

ConfirmModal never called useModalLock, so the page scrolled behind every
confirmation dialog (8+ usages). Add the ref-counted scroll lock and guard
backdrop-click against the loading state, matching FormModal.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/components/ConfirmModal.tsx

@@ -1,6 +1,7 @@
 import { useEffect, type ReactNode } from "react";
 import { motion, AnimatePresence } from "framer-motion";
 import useReducedMotion from "../hooks/useReducedMotion";
+import useModalLock from "../hooks/useModalLock";
 
 interface ConfirmModalProps {
   isOpen: boolean;
@@ -93,6 +94,8 @@ export default function ConfirmModal({
   loading,
 }: ConfirmModalProps) {
   const reducedMotion = useReducedMotion();
+  // Lock body scroll while open (ref-counted, nesting-safe) — matches FormModal.
+  useModalLock(isOpen);
   useEffect(() => {
     if (!isOpen) return;
 
@@ -119,7 +122,10 @@ export default function ConfirmModal({
           exit={{ opacity: 0 }}
           transition={{ duration: reducedMotion ? 0 : 0.18 }}
         >
-          <div className="admin-modal-backdrop" onClick={onClose} />
+          <div
+            className="admin-modal-backdrop"
+            onClick={() => !loading && onClose()}
+          />
           <motion.div
             className="admin-modal admin-confirm-modal"
             role="dialog"