feat: show processing status for one-off campaigns (#14592)

## Summary

One-off SMS and WhatsApp campaigns now show a `Processing` state while
the audience send is in progress. The campaign moves to `Completed`
after processing finishes, and already-processing campaigns are skipped
by the scheduler to avoid duplicate sends.

## Closes

- [CW-6037: feat: Introduce an in-progress status for
campaigns](https://linear.app/chatwoot/issue/CW-6037/feat-introduce-an-in-progress-status-for-campaigns)

## Screenshot

SMS campaign card showing the new `Processing` status.

<img width="3840" height="2160" alt="framed-campaign-processing-status"
src="https://github.com/user-attachments/assets/de7913b5-65fb-4121-9034-24a568eb0382"
/>

## What changed

- Added `processing` as a campaign status.
- Mark one-off campaigns as `processing` under a row lock before the
send service runs.
- Complete SMS, Twilio SMS, and WhatsApp one-off campaigns after
audience processing finishes.
- Keep campaigns in `processing` if an unexpected service error escapes,
so the scheduler does not automatically resend the audience.
- Added the `Processing` label for SMS and WhatsApp campaign cards.

## Known operational behavior

If a worker is interrupted or an unexpected service error escapes after
a campaign is marked `processing`, the campaign can remain in
`processing`. This is intentional for now to avoid automatic
full-audience resends. Installation admins can decide whether to mark
the campaign completed or restart it manually from the Rails console
after checking what was sent.

## How to test

- Create a one-off SMS or WhatsApp campaign scheduled for now.
- Run the scheduled job or trigger the campaign job.
- Confirm the campaign card shows `Processing` while the audience is
being processed. For small audiences, refresh during processing or use a
larger audience so the state is observable.
- Confirm the campaign moves to `Completed` after audience processing
finishes.
- Confirm an already-processing campaign is not enqueued again by the
scheduled job.

spec/services/sms/oneoff_sms_campaign_service_spec.rb

@@ -45,6 +45,19 @@ describe Sms::OneoffSmsCampaignService do
       expect(campaign.reload.completed?).to be true
     end
 
+    it 'marks the campaign completed after processing the audience' do
+      contact = create(:contact, :with_phone_number, account: account)
+      contact.update_labels([label1.title])
+
+      expect(sms_channel).to receive(:send_text_message) do
+        expect(campaign.reload.completed?).to be false
+      end
+
+      sms_campaign_service.perform
+
+      expect(campaign.reload.completed?).to be true
+    end
+
     it 'uses liquid template service to process campaign message' do
       contact = create(:contact, :with_phone_number, account: account)
       contact.update_labels([label1.title])

spec/services/twilio/oneoff_sms_campaign_service_spec.rb

@@ -61,6 +61,24 @@ describe Twilio::OneoffSmsCampaignService do
       expect(campaign.reload.completed?).to be true
     end
 
+    it 'marks the campaign completed after processing the audience' do
+      contact = create(:contact, :with_phone_number, account: account)
+      contact.update_labels([label1.title])
+
+      expect(twilio_messages).to receive(:create).with(
+        body: campaign.message,
+        messaging_service_sid: twilio_sms.messaging_service_sid,
+        to: contact.phone_number,
+        status_callback: 'http://localhost:3000/twilio/delivery_status'
+      ) do
+        expect(campaign.reload.completed?).to be false
+      end
+
+      sms_campaign_service.perform
+
+      expect(campaign.reload.completed?).to be true
+    end
+
     it 'uses liquid template service to process campaign message' do
       contact = create(:contact, :with_phone_number, account: account)
       contact.update_labels([label1.title])

spec/services/whatsapp/oneoff_campaign_service_spec.rb

@@ -82,6 +82,19 @@ describe Whatsapp::OneoffCampaignService do
         expect(campaign.reload.completed?).to be true
       end
 
+      it 'marks the campaign completed after processing the audience' do
+        contact = create(:contact, :with_phone_number, account: account)
+        contact.update_labels([label1.title])
+
+        expect(whatsapp_channel).to receive(:send_template) do
+          expect(campaign.reload.completed?).to be false
+        end
+
+        described_class.new(campaign: campaign).perform
+
+        expect(campaign.reload.completed?).to be true
+      end
+
       it 'processes contacts with matching labels' do
         contact_with_label1, contact_with_label2, contact_with_both_labels =
           create_list(:contact, 3, :with_phone_number, account: account)