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

spec/jobs/webhooks/instagram_events_job_spec.rb

@@ -7,6 +7,10 @@ describe Webhooks::InstagramEventsJob do
     stub_request(:post, /graph\.facebook\.com/)
     stub_request(:get, 'https://www.example.com/test.jpeg')
       .to_return(status: 200, body: '', headers: {})
+    stub_request(:get, 'https://lookaside.fbsbx.com/ig_messaging_cdn/?asset_id=17949487764033669&signature=test')
+      .to_return(status: 200, body: '', headers: {})
+    stub_request(:get, 'https://lookaside.fbsbx.com/ig_messaging_cdn/?asset_id=18091626484740369&signature=test')
+      .to_return(status: 200, body: '', headers: {})
   end
 
   let!(:account) { create(:account) }
@@ -131,6 +135,52 @@ describe Webhooks::InstagramEventsJob do
         expect(attachment.push_event_data[:data_url]).to eq(attachment.external_url)
       end
 
+      it 'creates incoming message with ig_story attachment in the instagram inbox' do
+        ig_story_event = build(:instagram_ig_story_event).with_indifferent_access
+        sender_id = ig_story_event[:entry][0][:messaging][0][:sender][:id]
+
+        allow(Koala::Facebook::API).to receive(:new).and_return(fb_object)
+        allow(fb_object).to receive(:get_object).and_return(
+          return_object_for(sender_id).with_indifferent_access
+        )
+
+        instagram_webhook.perform_now(ig_story_event[:entry])
+
+        expect(instagram_messenger_inbox.messages.count).to be 1
+        expect(instagram_messenger_inbox.messages.last.attachments.count).to be 1
+
+        message = instagram_messenger_inbox.messages.last
+        attachment = message.attachments.last
+
+        expect(attachment.file_type).to eq 'ig_story'
+        expect(attachment.external_url).to include 'lookaside.fbsbx.com'
+        expect(message.content).to eq 'Shared story'
+        expect(message.content_attributes['image_type']).to eq 'ig_story'
+      end
+
+      it 'creates incoming message with ig_post attachment in the instagram inbox' do
+        ig_post_event = build(:instagram_ig_post_event).with_indifferent_access
+        sender_id = ig_post_event[:entry][0][:messaging][0][:sender][:id]
+
+        allow(Koala::Facebook::API).to receive(:new).and_return(fb_object)
+        allow(fb_object).to receive(:get_object).and_return(
+          return_object_for(sender_id).with_indifferent_access
+        )
+
+        instagram_webhook.perform_now(ig_post_event[:entry])
+
+        expect(instagram_messenger_inbox.messages.count).to be 1
+        expect(instagram_messenger_inbox.messages.last.attachments.count).to be 1
+
+        message = instagram_messenger_inbox.messages.last
+        attachment = message.attachments.last
+
+        expect(attachment.file_type).to eq 'ig_post'
+        expect(attachment.external_url).to include 'ig_messaging_cdn'
+        expect(message.content).to eq 'Shared post'
+        expect(message.content_attributes['image_type']).to eq 'ig_post'
+      end
+
       it 'does not create contact or messages when Facebook API call fails' do
         story_mention_echo_event = build(:instagram_story_mention_event_with_echo).with_indifferent_access
 
@@ -262,6 +312,38 @@ describe Webhooks::InstagramEventsJob do
         expect(instagram_inbox.messages.last.content_attributes['is_unsupported']).to be true
       end
 
+      it 'creates incoming message with ig_story attachment in the instagram direct inbox' do
+        ig_story_event = build(:instagram_ig_story_event).with_indifferent_access
+        instagram_webhook.perform_now(ig_story_event[:entry])
+
+        expect(instagram_inbox.messages.count).to be 1
+        expect(instagram_inbox.messages.last.attachments.count).to be 1
+
+        message = instagram_inbox.messages.last
+        attachment = message.attachments.last
+
+        expect(attachment.file_type).to eq 'ig_story'
+        expect(attachment.external_url).to include 'lookaside.fbsbx.com'
+        expect(message.content).to eq 'Shared story'
+        expect(message.content_attributes['image_type']).to eq 'ig_story'
+      end
+
+      it 'creates incoming message with ig_post attachment in the instagram direct inbox' do
+        ig_post_event = build(:instagram_ig_post_event).with_indifferent_access
+        instagram_webhook.perform_now(ig_post_event[:entry])
+
+        expect(instagram_inbox.messages.count).to be 1
+        expect(instagram_inbox.messages.last.attachments.count).to be 1
+
+        message = instagram_inbox.messages.last
+        attachment = message.attachments.last
+
+        expect(attachment.file_type).to eq 'ig_post'
+        expect(attachment.external_url).to include 'ig_messaging_cdn'
+        expect(message.content).to eq 'Shared post'
+        expect(message.content_attributes['image_type']).to eq 'ig_post'
+      end
+
       it 'does not create contact or messages when Instagram API call fails' do
         story_mention_echo_event = build(:instagram_story_mention_event_with_echo).with_indifferent_access