feat: Add twilio content templates (#12277)

Implements comprehensive Twilio WhatsApp content template support (Phase
1) enabling text, media, and quick reply templates with proper parameter
conversion, sync capabilities, and feature flag protection.

###  Features Implemented

  **Template Types Supported**

  - Basic Text Templates: Simple text with variables ({{1}}, {{2}})
  - Media Templates: Image/Video/Document templates with text variables
  - Quick Reply Templates: Interactive button templates
- Phase 2 (Future): List Picker, Call-to-Action, Catalog, Carousel,
Authentication templates

  **Template Synchronization**

- API Endpoint: POST
/api/v1/accounts/{account_id}/inboxes/{inbox_id}/sync_templates
  - Background Job: Channels::Twilio::TemplatesSyncJob
  - Storage: JSONB format in channel_twilio_sms.content_templates
  - Auto-categorization: UTILITY, MARKETING, AUTHENTICATION categories

 ###  Template Examples Tested


  #### Text template
```
  { "name": "greet", "language": "en" }
```
  #### Template with variables
```
  { "name": "order_status", "parameters": [{"type": "body", "parameters": [{"text": "John"}]}] }
```

  #### Media template with image
```
  { "name": "product_showcase", "parameters": [
    {"type": "header", "parameters": [{"image": {"link": "image.jpg"}}]},
    {"type": "body", "parameters": [{"text": "iPhone"}, {"text": "$999"}]}
  ]}
```
#### Preview

<img width="1362" height="1058" alt="CleanShot 2025-08-26 at 10 01
51@2x"
src="https://github.com/user-attachments/assets/cb280cea-08c3-44ca-8025-58a96cb3a451"
/>

<img width="1308" height="1246" alt="CleanShot 2025-08-26 at 10 02
02@2x"
src="https://github.com/user-attachments/assets/9ea8537a-61e9-40f5-844f-eaad337e1ddd"
/>

#### User guide

https://www.chatwoot.com/hc/user-guide/articles/1756195741-twilio-content-templates

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/javascript/dashboard/components/widgets/WootWriter/ReplyBottomPanel.vue

@@ -95,6 +95,10 @@ export default {
       type: Boolean,
       default: false,
     },
+    enableContentTemplates: {
+      type: Boolean,
+      default: false,
+    },
     conversationId: {
       type: Number,
       required: true,
@@ -121,6 +125,7 @@ export default {
     'toggleInsertArticle',
     'toggleEditor',
     'selectWhatsappTemplate',
+    'selectContentTemplate',
   ],
   setup() {
     const { setSignatureFlagForInbox, fetchSignatureFlagFromUISettings } =
@@ -347,6 +352,15 @@ export default {
         sm
         @click="$emit('selectWhatsappTemplate')"
       />
+      <NextButton
+        v-if="enableContentTemplates"
+        v-tooltip.top-end="'Content Templates'"
+        icon="i-ph-whatsapp-logo"
+        slate
+        faded
+        sm
+        @click="$emit('selectContentTemplate')"
+      />
       <VideoCallButton
         v-if="(isAWebWidgetInbox || isAPIInbox) && !isOnPrivateNote"
         :conversation-id="conversationId"
@@ -361,7 +375,7 @@ export default {
       <transition name="modal-fade">
         <div
           v-show="uploadRef && uploadRef.dropActive"
-          class="fixed top-0 bottom-0 left-0 right-0 z-20 flex flex-col items-center justify-center w-full h-full gap-2 text-n-slate-12 bg-modal-backdrop-light dark:bg-modal-backdrop-dark"
+          class="flex fixed top-0 right-0 bottom-0 left-0 z-20 flex-col gap-2 justify-center items-center w-full h-full text-n-slate-12 bg-modal-backdrop-light dark:bg-modal-backdrop-dark"
         >
           <fluent-icon icon="cloud-backup" size="40" />
           <h4 class="text-2xl break-words text-n-slate-12">