fix(whatsapp): refresh inboxes when opening new conversation composer (#15337)

When an agent starts a new conversation, the WhatsApp template picker in
the composer only shows templates that were already loaded into the
frontend store — it doesn't refresh when the composer opens. If a
template sync completed after the store was last populated, the newly
synced template shows up on the inbox's Settings > Templates page (which
always refetches on load) but not in the New Conversation composer,
since that view relied solely on the account-cache-invalidated websocket
event, which doesn't always reach an already-open session in time.

## What changed
- `ComposeConversation.vue` now dispatches a cache-aware `inboxes/get`
refetch every time the composer popover opens, so the WhatsApp template
list is current before an agent picks a template to message a customer.
The refetch checks the account's cache key first and only re-pulls the
full inbox list when it's actually stale, so it stays cheap in the
common case.

## How to reproduce
1. Sync/update WhatsApp templates for an inbox (e.g. via Settings >
Inboxes > [WhatsApp inbox] > Sync Templates).
2. Without reloading the page, open the New Conversation composer for
that inbox and check the WhatsApp template picker — a newly synced
template may be missing until this fix.

---------

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

app/javascript/dashboard/components-next/NewConversation/ComposeConversation.vue

@@ -201,6 +201,9 @@ const onPopoverShow = () => {
   // Flag to prevent triggering drag n drop,
   // When compose modal is active
   emitter.emit(BUS_EVENTS.NEW_CONVERSATION_MODAL, true);
+  // Cache-aware refetch, so newly synced WhatsApp templates show up here
+  // even if the account-cache-invalidated websocket event was missed.
+  store.dispatch('inboxes/get');
 };
 
 const onPopoverHide = () => {

app/javascript/dashboard/components-next/NewConversation/components/WhatsAppOptions.vue

@@ -21,10 +21,15 @@ const { t } = useI18n();
 const getFilteredWhatsAppTemplates = useMapGetter(
   'inboxes/getFilteredWhatsAppTemplates'
 );
+const inboxesUiFlags = useMapGetter('inboxes/getUIFlags');
 
 const searchQuery = ref('');
 const selectedTemplate = ref(null);
 
+// Gates the trigger while ComposeConversation's on-open refetch is in flight,
+// so an agent can't open the picker before a stale template list is refreshed.
+const isRefreshingTemplates = computed(() => inboxesUiFlags.value.isFetching);
+
 const whatsAppTemplateMessages = computed(() => {
   return getFilteredWhatsAppTemplates.value(props.inboxId);
 });
@@ -74,7 +79,7 @@ const handleSendMessage = (template, hide) => {
       :label="t('COMPOSE_NEW_CONVERSATION.FORM.WHATSAPP_OPTIONS.LABEL')"
       color="slate"
       size="sm"
-      :disabled="selectedTemplate"
+      :disabled="selectedTemplate || isRefreshingTemplates"
       class="!text-xs font-medium"
     />
     <template #content="{ hide }">