fix: Prevent article editor from resetting content while typing (#14014)

# Pull Request Template

## Description


### Description

This PR fixes an issue where the editor would reset content and move the
cursor while typing. The issue was caused by a dual debounce setup
(400ms + 2500ms) that saved content and then overwrote local state with
stale API responses while the user was still typing.

### What changed

* Editor now uses local state (`localTitle`, `localContent`) as the
source of truth while editing
* Vuex store is only used on initial load or navigation
* Replaced dual debounce with a single 500ms debounce (fewer API calls)
* `UPDATE_ARTICLE` now merges updates instead of replacing the article
  * Prevents status changes from wiping unsaved content
* Removed `updateAsync` for a simpler update flow

### How it works

User types
→ local ref updates immediately (editor reads from this)
→ 500ms debounce triggers
→ dispatches `articles/update`
→ API persists the change
→ on success: store merges the response (used by other components)
→ editor remains unaffected (continues using local state)



Fixes
https://linear.app/chatwoot/issue/CW-6727/better-syncing-of-content-the-editor-randomly-updates-the-content

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

1. Open any Help Center article for editing
2. Type continuously for a few seconds — content should not reset or
jump
3. Change article status (publish/archive/draft) while editing — content
should remain intact
4. Test on a slow network (use DevTools throttling) — typing should
remain smooth


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/routes/dashboard/helpcenter/pages/PortalsArticlesEditPage.vue

@@ -40,11 +40,10 @@ const articleLink = computed(() => {
   );
 });
 
-const saveArticle = async ({ ...values }, isAsync = false) => {
-  const actionToDispatch = isAsync ? 'articles/updateAsync' : 'articles/update';
+const saveArticle = async ({ ...values }) => {
   isUpdating.value = true;
   try {
-    await store.dispatch(actionToDispatch, {
+    await store.dispatch('articles/update', {
       portalSlug,
       articleId: articleSlug,
       ...values,
@@ -62,10 +61,6 @@ const saveArticle = async ({ ...values }, isAsync = false) => {
   }
 };
 
-const saveArticleAsync = async ({ ...values }) => {
-  saveArticle({ ...values }, true);
-};
-
 const isCategoryArticles = computed(() => {
   return (
     route.name === 'portals_categories_articles_index' ||
@@ -112,7 +107,6 @@ onMounted(fetchArticleDetails);
     :is-updating="isUpdating"
     :is-saved="isSaved"
     @save-article="saveArticle"
-    @save-article-async="saveArticleAsync"
     @preview-article="previewArticle"
     @go-back="goBackToArticles"
   />