feat(inbox): Enable conversation continuity for social channels (#11079)

## Summary
This PR enables and surfaces **conversation workflow** for social-style
channels that should support either:
- `Create new conversations` after resolve, or
- `Reopen same conversation`

## What is included
- Adds the conversation workflow setting UI as card-based options in
Inbox Settings.
- Expands channel availability in settings to include channels like:
  - Telegram
  - TikTok
  - Instagram
  - Line
  - WhatsApp
  - Facebook
- Updates conversation selection behavior for Line incoming messages to
respect the workflow (reopen vs create-new-after-resolved).
- Updates TikTok conversation selection behavior to respect the workflow
(reopen vs create-new-after-resolved).
- Keeps email behavior unchanged (always starts a new thread).

Fixes: https://github.com/chatwoot/chatwoot/issues/8426

## Screenshot

<img width="1400" height="900" alt="pr11079-workflow-sender-clear-tight"
src="https://github.com/user-attachments/assets/9456821f-8d83-4924-8dcf-7503c811a7b1"
/>


## How To Reproduce
1. Open `Settings -> Inboxes ->
<Telegram/TikTok/Instagram/Line/Facebook/WhatsApp inbox> -> Settings`.
2. Verify **Conversation workflow** is visible with the two card
options.
3. Toggle between both options and save.
4. For Line and TikTok, verify resolved-conversation behavior follows
the selected workflow.

## Testing
- `RAILS_ENV=test bundle exec rspec
spec/builders/messages/instagram/message_builder_spec.rb:213
spec/builders/messages/instagram/message_builder_spec.rb:255
spec/builders/messages/instagram/messenger/message_builder_spec.rb:228
spec/builders/messages/instagram/messenger/message_builder_spec.rb:293
spec/services/tiktok/message_service_spec.rb`
- Result: `16 examples, 0 failures`

## Follow-up
- Migrate Website Live Chat workflow settings into this same
conversation-workflow settings model.
- Add Voice channel support for this workflow setting.

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>

spec/services/line/incoming_message_service_spec.rb

@@ -405,5 +405,111 @@ describe Line::IncomingMessageService do
         expect(line_channel.inbox.messages.first.attachments.first.file.blob.filename.to_s).to eq('contacts.csv')
       end
     end
+
+    context 'when lock_to_single_conversation is false' do
+      before do
+        line_channel.inbox.update(lock_to_single_conversation: false)
+      end
+
+      it 'creates a new conversation when all previous conversations are resolved' do
+        line_bot = double
+        line_user_profile = double
+        allow(Line::Bot::Client).to receive(:new).and_return(line_bot)
+        allow(line_bot).to receive(:get_profile).and_return(line_user_profile)
+        allow(line_user_profile).to receive(:body).and_return(
+          {
+            'displayName': 'LINE Test',
+            'userId': 'U4af4980629',
+            'pictureUrl': 'https://test.com'
+          }.to_json
+        )
+
+        # Create a contact and a resolved conversation
+        described_class.new(inbox: line_channel.inbox, params: params).perform
+
+        # Mark the conversation as resolved
+        conversation = line_channel.inbox.conversations.last
+        conversation.update(status: :resolved)
+
+        # Send a new message
+        new_params = params.deep_dup
+        new_params[:events][0][:message][:id] = '325709'
+        new_params[:events][0][:message][:text] = 'Second message'
+
+        described_class.new(inbox: line_channel.inbox, params: new_params).perform
+
+        # Should create a new conversation
+        expect(line_channel.inbox.conversations.count).to eq(2)
+        expect(line_channel.inbox.conversations.last.messages.first.content).to eq('Second message')
+      end
+
+      it 'uses the existing conversation when there is an unresolved conversation' do
+        line_bot = double
+        line_user_profile = double
+        allow(Line::Bot::Client).to receive(:new).and_return(line_bot)
+        allow(line_bot).to receive(:get_profile).and_return(line_user_profile)
+        allow(line_user_profile).to receive(:body).and_return(
+          {
+            'displayName': 'LINE Test',
+            'userId': 'U4af4980629',
+            'pictureUrl': 'https://test.com'
+          }.to_json
+        )
+
+        # Create a contact and an unresolved conversation
+        described_class.new(inbox: line_channel.inbox, params: params).perform
+
+        # Send a new message
+        new_params = params.deep_dup
+        new_params[:events][0][:message][:id] = '325709'
+        new_params[:events][0][:message][:text] = 'Second message'
+
+        described_class.new(inbox: line_channel.inbox, params: new_params).perform
+
+        # Should use the same conversation
+        expect(line_channel.inbox.conversations.count).to eq(1)
+        expect(line_channel.inbox.conversations.last.messages.count).to eq(2)
+        expect(line_channel.inbox.conversations.last.messages.last.content).to eq('Second message')
+      end
+    end
+
+    context 'when lock_to_single_conversation is true' do
+      before do
+        line_channel.inbox.update(lock_to_single_conversation: true)
+      end
+
+      it 'uses the existing conversation even when it is resolved' do
+        line_bot = double
+        line_user_profile = double
+        allow(Line::Bot::Client).to receive(:new).and_return(line_bot)
+        allow(line_bot).to receive(:get_profile).and_return(line_user_profile)
+        allow(line_user_profile).to receive(:body).and_return(
+          {
+            'displayName': 'LINE Test',
+            'userId': 'U4af4980629',
+            'pictureUrl': 'https://test.com'
+          }.to_json
+        )
+
+        # Create a contact and a resolved conversation
+        described_class.new(inbox: line_channel.inbox, params: params).perform
+
+        # Mark the conversation as resolved
+        conversation = line_channel.inbox.conversations.last
+        conversation.update(status: :resolved)
+
+        # Send a new message
+        new_params = params.deep_dup
+        new_params[:events][0][:message][:id] = '325709'
+        new_params[:events][0][:message][:text] = 'Second message'
+
+        described_class.new(inbox: line_channel.inbox, params: new_params).perform
+
+        # Should use the same conversation
+        expect(line_channel.inbox.conversations.count).to eq(1)
+        expect(line_channel.inbox.conversations.last.messages.count).to eq(2)
+        expect(line_channel.inbox.conversations.last.messages.last.content).to eq('Second message')
+      end
+    end
   end
 end