feat: Added the backend support for twilio content templates (#12272)

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

 **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
  
 Front end changes is available via #12277

---------

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

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2025_08_08_123008) do
+ActiveRecord::Schema[7.1].define(version: 2025_08_22_061042) do
   # These extensions should be enabled to support this database
   enable_extension "pg_stat_statements"
   enable_extension "pg_trgm"
@@ -474,6 +474,8 @@ ActiveRecord::Schema[7.1].define(version: 2025_08_08_123008) do
     t.integer "medium", default: 0
     t.string "messaging_service_sid"
     t.string "api_key_sid"
+    t.jsonb "content_templates", default: {}
+    t.datetime "content_templates_last_updated"
     t.index ["account_sid", "phone_number"], name: "index_channel_twilio_sms_on_account_sid_and_phone_number", unique: true
     t.index ["messaging_service_sid"], name: "index_channel_twilio_sms_on_messaging_service_sid", unique: true
     t.index ["phone_number"], name: "index_channel_twilio_sms_on_phone_number", unique: true