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/i18n/locale/en/contact.json

@@ -612,6 +612,15 @@
           "SEND_MESSAGE": "Send message"
         }
       },
+      "TWILIO_OPTIONS": {
+        "LABEL": "Select template",
+        "SEARCH_PLACEHOLDER": "Search templates",
+        "EMPTY_STATE": "No templates found",
+        "TEMPLATE_PARSER": {
+          "BACK": "Go back",
+          "SEND_MESSAGE": "Send message"
+        }
+      },
       "ACTION_BUTTONS": {
         "DISCARD": "Discard",
         "SEND": "Send ({keyCode})"

app/javascript/dashboard/i18n/locale/en/contentTemplates.json

@@ -0,0 +1,51 @@
+{
+  "CONTENT_TEMPLATES": {
+    "MODAL": {
+      "TITLE": "Twilio Templates",
+      "SUBTITLE": "Select the Twilio template you want to send",
+      "TEMPLATE_SELECTED_SUBTITLE": "Configure template: {templateName}"
+    },
+    "PICKER": {
+      "SEARCH_PLACEHOLDER": "Search Templates",
+      "NO_TEMPLATES_FOUND": "No templates found for",
+      "NO_CONTENT": "No content",
+      "HEADER": "Header",
+      "BODY": "Body",
+      "FOOTER": "Footer",
+      "BUTTONS": "Buttons",
+      "CATEGORY": "Category",
+      "MEDIA_CONTENT": "Media Content",
+      "MEDIA_CONTENT_FALLBACK": "media content",
+      "NO_TEMPLATES_AVAILABLE": "No Twilio templates available. Click refresh to sync templates from Twilio.",
+      "REFRESH_BUTTON": "Refresh templates",
+      "REFRESH_SUCCESS": "Templates refresh initiated. It may take a couple of minutes to update.",
+      "REFRESH_ERROR": "Failed to refresh templates. Please try again.",
+      "LABELS": {
+        "LANGUAGE": "Language",
+        "TEMPLATE_BODY": "Template Body",
+        "CATEGORY": "Category"
+      },
+      "TYPES": {
+        "MEDIA": "Media",
+        "QUICK_REPLY": "Quick Reply",
+        "TEXT": "Text"
+      }
+    },
+    "PARSER": {
+      "VARIABLES_LABEL": "Variables",
+      "LANGUAGE": "Language",
+      "CATEGORY": "Category",
+      "VARIABLE_PLACEHOLDER": "Enter {variable} value",
+      "GO_BACK_LABEL": "Go Back",
+      "SEND_MESSAGE_LABEL": "Send Message",
+      "FORM_ERROR_MESSAGE": "Please fill all variables before sending",
+      "MEDIA_HEADER_LABEL": "{type} Header",
+      "MEDIA_URL_LABEL": "Enter full media URL",
+      "MEDIA_URL_PLACEHOLDER": "https://example.com/image.jpg"
+    },
+    "FORM": {
+      "BACK_BUTTON": "Back",
+      "SEND_MESSAGE_BUTTON": "Send Message"
+    }
+  }
+}

app/javascript/dashboard/i18n/locale/en/index.js

@@ -35,6 +35,7 @@ import signup from './signup.json';
 import sla from './sla.json';
 import teamsSettings from './teamsSettings.json';
 import whatsappTemplates from './whatsappTemplates.json';
+import contentTemplates from './contentTemplates.json';
 
 export default {
   ...advancedFilters,
@@ -74,4 +75,5 @@ export default {
   ...sla,
   ...teamsSettings,
   ...whatsappTemplates,
+  ...contentTemplates,
 };