feat(js): harden global HTTP and module import contracts

web/js/components/app-flash-auto-dismiss.js

@@ -3,6 +3,7 @@
  * Supports slide-out animation and hover-pause.
  */
 import { resolveHost } from '../core/app-dom.js';
+import { postForm as postFormRequest } from '../core/app-http.js';
 
 export function initFlashAutoDismiss(root = document, options = {}) {
   const {
@@ -32,17 +33,14 @@ export function initFlashAutoDismiss(root = document, options = {}) {
   const postForm = async (form) => {
     const action = form.getAttribute('action');
     if (!action) {
-      return null;
+      return false;
+    }
+    try {
+      await postFormRequest(action, new FormData(form));
+      return true;
+    } catch {
+      return false;
     }
-    const body = new URLSearchParams(new FormData(form));
-    return fetch(action, {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/x-www-form-urlencoded',
-        'X-Requested-With': 'fetch',
-      },
-      body,
-    });
   };
 
   notices.forEach((notice) => {
@@ -62,8 +60,8 @@ export function initFlashAutoDismiss(root = document, options = {}) {
       }
       const form = notice.querySelector('form');
       if (form) {
-        const response = await postForm(form);
-        if (!response || !response.ok) {
+        const ok = await postForm(form);
+        if (!ok) {
           return;
         }
       }
@@ -80,8 +78,8 @@ export function initFlashAutoDismiss(root = document, options = {}) {
         if (destroyed) return;
         const form = notice.querySelector('form');
         if (form) {
-          const response = await postForm(form);
-          if (!response || !response.ok) return;
+          const ok = await postForm(form);
+          if (!ok) return;
         }
         dismissNotice(notice);
       }, 1000);