feat: add job to remove stale contacts and contact_inboxes (#11186)

- Add a job to remove stale contacts and contact_inboxes across all accounts

Stale anonymous contact is defined as 
- have no identification (email, phone_number, and identifier are NULL)
- have no conversations
- are older than 30 days

---------

Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

spec/jobs/internal/process_stale_contacts_job_spec.rb

@@ -0,0 +1,34 @@
+require 'rails_helper'
+
+RSpec.describe Internal::ProcessStaleContactsJob do
+  subject(:job) { described_class.perform_later }
+
+  it 'enqueues the job' do
+    expect { job }.to have_enqueued_job(described_class)
+      .on_queue('scheduled_jobs')
+  end
+
+  it 'enqueues RemoveStaleContactsJob for each account' do
+    account1 = create(:account)
+    account2 = create(:account)
+    account3 = create(:account)
+
+    expect { described_class.perform_now }.to have_enqueued_job(Internal::RemoveStaleContactsJob)
+      .with(account1)
+      .on_queue('low')
+    expect { described_class.perform_now }.to have_enqueued_job(Internal::RemoveStaleContactsJob)
+      .with(account2)
+      .on_queue('low')
+    expect { described_class.perform_now }.to have_enqueued_job(Internal::RemoveStaleContactsJob)
+      .with(account3)
+      .on_queue('low')
+  end
+
+  it 'processes accounts in batches' do
+    account = create(:account)
+    allow(Account).to receive(:find_in_batches).with(batch_size: 100).and_yield([account])
+
+    expect(Internal::RemoveStaleContactsJob).to receive(:perform_later).with(account)
+    described_class.perform_now
+  end
+end

spec/jobs/internal/remove_stale_contacts_job_spec.rb

@@ -0,0 +1,20 @@
+require 'rails_helper'
+
+RSpec.describe Internal::RemoveStaleContactsJob do
+  subject(:job) { described_class.perform_later(account) }
+
+  let(:account) { create(:account) }
+
+  it 'enqueues the job' do
+    expect { job }.to have_enqueued_job(described_class)
+      .with(account)
+      .on_queue('low')
+  end
+
+  it 'calls the RemoveStaleContactsService' do
+    service = instance_double(Internal::RemoveStaleContactsService)
+    expect(Internal::RemoveStaleContactsService).to receive(:new).with(account: account).and_return(service)
+    expect(service).to receive(:perform)
+    described_class.perform_now(account)
+  end
+end