feat: Handle external echo messages from native apps (#13371)

When businesses use WhatsApp Business App (co-existence mode) or
Instagram App or TikTok alongside Chatwoot, messages sent from the
native apps were not synced properly back to Chatwoot. This left agents
with an incomplete conversation history and no visibility into responses
sent outside the dashboard. Additionally, if these echo messages did
arrive, they appeared as "Sent by: Bot" in the UI since they had no
sender, making it confusing for agents.

This PR subscribes to WhatsApp `smb_message_echoes` webhook events and
routes them through the existing service with an `outgoing_echo` flag,
mirroring how Instagram already handles echoes. On the Instagram side,
echo messages now also carry the `external_echo` content attribute and
`delivered` status.

On the frontend, messages with `externalEcho` are distinguished from bot
messages showing a "Native app" avatar and an advisory note encouraging
agents to reply from Chatwoot to maintain the service window.

<img width="1518" height="524" alt="CleanShot 2026-01-29 at 13 37 57@2x"
src="https://github.com/user-attachments/assets/5aa0b552-6382-441f-96aa-9a62ca716e4a"
/>


Fixes
https://linear.app/chatwoot/issue/CW-4204/display-messages-not-sent-from-chatwoot-in-case-of-outgoing-echo
Fixes
https://linear.app/chatwoot/issue/PLA-33/incoming-from-me-messages-from-whatsapp-business-app-are-not-falling

app/jobs/webhooks/tiktok_events_job.rb

@@ -54,7 +54,7 @@ class Webhooks::TiktokEventsJob < MutexApplicationJob
   # Receive real-time notifications if you send a message to a user.
   def im_send_msg
     # This can be either an echo message or a message sent directly via tiktok application
-    ::Tiktok::MessageService.new(channel: channel, content: content).perform
+    ::Tiktok::MessageService.new(channel: channel, content: content, outgoing_echo: true).perform
   end
 
   # Receive real-time notifications if a user outside the European Economic Area (EEA), Switzerland, or the UK sends a message to you.

app/jobs/webhooks/whatsapp_events_job.rb

@@ -9,6 +9,56 @@ class Webhooks::WhatsappEventsJob < ApplicationJob
       return
     end
 
+    if message_echo_event?(params)
+      handle_message_echo(channel, params)
+    else
+      handle_message_events(channel, params)
+    end
+  end
+
+  # Detects if the webhook is an SMB message echo event (message sent from WhatsApp Business app)
+  # This is part of WhatsApp coexistence feature where businesses can respond from both
+  # Chatwoot and the WhatsApp Business app, with messages synced to Chatwoot.
+  #
+  # Regular message payload (field: "messages"):
+  # {
+  #   "entry": [{
+  #     "changes": [{
+  #       "field": "messages",
+  #       "value": {
+  #         "contacts": [{ "wa_id": "919745786257", "profile": { "name": "Customer" } }],
+  #         "messages": [{ "from": "919745786257", "id": "wamid...", "text": { "body": "Hello" } }]
+  #       }
+  #     }]
+  #   }]
+  # }
+  #
+  # Echo message payload (field: "smb_message_echoes"):
+  # {
+  #   "entry": [{
+  #     "changes": [{
+  #       "field": "smb_message_echoes",
+  #       "value": {
+  #         "message_echoes": [{ "from": "971545296927", "to": "919745786257", "id": "wamid...", "text": { "body": "Hi" } }]
+  #       }
+  #     }]
+  #   }]
+  # }
+  #
+  # Key differences:
+  # - field: "smb_message_echoes" instead of "messages"
+  # - message_echoes[] instead of messages[]
+  # - "from" is the business number, "to" is the contact (reversed from regular messages)
+  # - No "contacts" array in echo payload
+  def message_echo_event?(params)
+    params.dig(:entry, 0, :changes, 0, :field) == 'smb_message_echoes'
+  end
+
+  def handle_message_echo(channel, params)
+    Whatsapp::IncomingMessageWhatsappCloudService.new(inbox: channel.inbox, params: params, outgoing_echo: true).perform
+  end
+
+  def handle_message_events(channel, params)
     case channel.provider
     when 'whatsapp_cloud'
       Whatsapp::IncomingMessageWhatsappCloudService.new(inbox: channel.inbox, params: params).perform