feat(js): add app-http contracts and migrate helpdesk runtime layer

web/js/pages/app-list-utils.js

@@ -1,3 +1,5 @@
+import { postForm as postFormRequest } from '../core/app-http.js';
+
 export const buildUrl = (appBase, path) => new URL(path, appBase).toString();
 
 export const getAppBase = () => {
@@ -125,15 +127,7 @@ export const buildBadgeList = (items, options = {}) => {
 
 export const postAction = async (url, csrf, data = {}) => {
   const body = new URLSearchParams({ ...data, [csrf.key]: csrf.token });
-  return fetch(url, {
-    method: 'POST',
-    headers: {
-      'Content-Type': 'application/x-www-form-urlencoded',
-      'Accept': 'application/json',
-      'X-Requested-With': 'fetch'
-    },
-    body
-  });
+  return postFormRequest(url, body);
 };
 
 export const badgeHtml = (gridjs, value = '') => {