feat: Add support for shared post and story attachment types in Instagram messages (#12997)

When users share Instagram posts or stories via DM, Instagram sends
webhooks with type `ig_post` and `ig_story` attachments. The system was
failing on these types because they weren't defined in the file_types.
This PR fixes the issue by handling all shared types and rendering them
on the front end.

**Shared post**

<img width="2154" height="1828" alt="CleanShot 2025-12-03 at 16 29
14@2x"
src="https://github.com/user-attachments/assets/7e731171-4904-43a6-abeb-b1db2c262742"
/>

**Shared status**
<img width="1702" height="1676" alt="CleanShot 2025-12-03 at 16 10
25@2x"
src="https://github.com/user-attachments/assets/6a151233-ce47-429d-b7c2-061514b20e05"
/>


Fixes
https://linear.app/chatwoot/issue/CW-5441/argumenterror-ig-story-is-not-a-valid-file-type-argumenterror

app/builders/messages/messenger/message_builder.rb

@@ -9,6 +9,8 @@ class Messages::Messenger::MessageBuilder
     attachment_obj.save!
     attach_file(attachment_obj, attachment_params(attachment)[:remote_file_url]) if attachment_params(attachment)[:remote_file_url]
     fetch_story_link(attachment_obj) if attachment_obj.file_type == 'story_mention'
+    fetch_ig_story_link(attachment_obj) if attachment_obj.file_type == 'ig_story'
+    fetch_ig_post_link(attachment_obj) if attachment_obj.file_type == 'ig_post'
     update_attachment_file_type(attachment_obj)
   end
 
@@ -27,7 +29,7 @@ class Messages::Messenger::MessageBuilder
     file_type = attachment['type'].to_sym
     params = { file_type: file_type, account_id: @message.account_id }
 
-    if [:image, :file, :audio, :video, :share, :story_mention, :ig_reel, :ig_post].include? file_type
+    if [:image, :file, :audio, :video, :share, :story_mention, :ig_reel, :ig_post, :ig_story].include? file_type
       params.merge!(file_type_params(attachment))
     elsif file_type == :location
       params.merge!(location_params(attachment))
@@ -39,9 +41,17 @@ class Messages::Messenger::MessageBuilder
   end
 
   def file_type_params(attachment)
+    # Handle different URL field names for different attachment types
+    url = case attachment['type'].to_sym
+          when :ig_story
+            attachment['payload']['story_media_url']
+          else
+            attachment['payload']['url']
+          end
+
     {
-      external_url: attachment['payload']['url'],
-      remote_file_url: attachment['payload']['url']
+      external_url: url,
+      remote_file_url: url
     }
   end
 
@@ -68,6 +78,21 @@ class Messages::Messenger::MessageBuilder
     message.save!
   end
 
+  def fetch_ig_story_link(attachment)
+    message = attachment.message
+    # For ig_story, we don't have the same API call as story_mention, so we'll set it up similarly but with generic content
+    message.content_attributes[:image_type] = 'ig_story'
+    message.content = I18n.t('conversations.messages.instagram_shared_story_content')
+    message.save!
+  end
+
+  def fetch_ig_post_link(attachment)
+    message = attachment.message
+    message.content_attributes[:image_type] = 'ig_post'
+    message.content = I18n.t('conversations.messages.instagram_shared_post_content')
+    message.save!
+  end
+
   # This is a placeholder method to be overridden by child classes
   def get_story_object_from_source_id(_source_id)
     {}