chore(hub): clean up legacy Captain hub flow (#13640)

## Summary
This PR cleans up legacy Hub/Captain integration paths and simplifies
hub URL behavior coverage in tests.

## Changes
- remove legacy Captain account endpoint flow from `ChatwootHub`
- remove obsolete spec coverage tied to that retired flow
- keep hub URL handling centralized in `base_url` with enterprise
overlay precedence
- simplify hub URL specs to assert explicit static URL expectations
where applicable

## Reproduce
Run the focused hub specs from this branch:
- `bundle exec rspec spec/lib/chatwoot_hub_spec.rb
spec/enterprise/lib/chatwoot_hub_spec.rb`

## Testing
Validated locally with:
- `bundle exec rspec spec/lib/chatwoot_hub_spec.rb
spec/enterprise/lib/chatwoot_hub_spec.rb`
- `bundle exec rubocop lib/chatwoot_hub.rb spec/lib/chatwoot_hub_spec.rb
enterprise/lib/enterprise/chatwoot_hub.rb
spec/enterprise/lib/chatwoot_hub_spec.rb`

lib/chatwoot_hub.rb

@@ -1,12 +1,30 @@
 # TODO: lets use HTTParty instead of RestClient
 class ChatwootHub
-  BASE_URL = ENV.fetch('CHATWOOT_HUB_URL', 'https://hub.2.chatwoot.com')
-  PING_URL = "#{BASE_URL}/ping".freeze
-  REGISTRATION_URL = "#{BASE_URL}/instances".freeze
-  PUSH_NOTIFICATION_URL = "#{BASE_URL}/send_push".freeze
-  EVENTS_URL = "#{BASE_URL}/events".freeze
-  BILLING_URL = "#{BASE_URL}/billing".freeze
-  CAPTAIN_ACCOUNTS_URL = "#{BASE_URL}/instance_captain_accounts".freeze
+  DEFAULT_BASE_URL = 'https://hub.2.chatwoot.com'.freeze
+
+  def self.base_url
+    DEFAULT_BASE_URL
+  end
+
+  def self.ping_url
+    "#{base_url}/ping"
+  end
+
+  def self.registration_url
+    "#{base_url}/instances"
+  end
+
+  def self.push_notification_url
+    "#{base_url}/send_push"
+  end
+
+  def self.events_url
+    "#{base_url}/events"
+  end
+
+  def self.billing_base_url
+    "#{base_url}/billing"
+  end
 
   def self.installation_identifier
     identifier = InstallationConfig.find_by(name: 'INSTALLATION_IDENTIFIER')&.value
@@ -15,7 +33,7 @@ class ChatwootHub
   end
 
   def self.billing_url
-    "#{BILLING_URL}?installation_identifier=#{installation_identifier}"
+    "#{billing_base_url}?installation_identifier=#{installation_identifier}"
   end
 
   def self.pricing_plan
@@ -68,7 +86,7 @@ class ChatwootHub
     begin
       info = instance_config
       info = info.merge(instance_metrics) unless ENV['DISABLE_TELEMETRY']
-      response = RestClient.post(PING_URL, info.to_json, { content_type: :json, accept: :json })
+      response = RestClient.post(ping_url, info.to_json, { content_type: :json, accept: :json })
       parsed_response = JSON.parse(response)
     rescue *ExceptionList::REST_CLIENT_EXCEPTIONS => e
       Rails.logger.error "Exception: #{e.message}"
@@ -80,7 +98,7 @@ class ChatwootHub
 
   def self.register_instance(company_name, owner_name, owner_email)
     info = { company_name: company_name, owner_name: owner_name, owner_email: owner_email, subscribed_to_mailers: true }
-    RestClient.post(REGISTRATION_URL, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
+    RestClient.post(registration_url, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
   rescue *ExceptionList::REST_CLIENT_EXCEPTIONS => e
     Rails.logger.error "Exception: #{e.message}"
   rescue StandardError => e
@@ -89,32 +107,23 @@ class ChatwootHub
 
   def self.send_push(fcm_options)
     info = { fcm_options: fcm_options }
-    RestClient.post(PUSH_NOTIFICATION_URL, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
+    RestClient.post(push_notification_url, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
   rescue *ExceptionList::REST_CLIENT_EXCEPTIONS => e
     Rails.logger.error "Exception: #{e.message}"
   rescue StandardError => e
     ChatwootExceptionTracker.new(e).capture_exception
   end
 
-  def self.get_captain_settings(account)
-    info = {
-      installation_identifier: installation_identifier,
-      chatwoot_account_id: account.id,
-      account_name: account.name
-    }
-    HTTParty.post(CAPTAIN_ACCOUNTS_URL,
-                  body: info.to_json,
-                  headers: { 'Content-Type' => 'application/json', 'Accept' => 'application/json' })
-  end
-
   def self.emit_event(event_name, event_data)
     return if ENV['DISABLE_TELEMETRY']
 
     info = { event_name: event_name, event_data: event_data }
-    RestClient.post(EVENTS_URL, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
+    RestClient.post(events_url, info.merge(instance_config).to_json, { content_type: :json, accept: :json })
   rescue *ExceptionList::REST_CLIENT_EXCEPTIONS => e
     Rails.logger.error "Exception: #{e.message}"
   rescue StandardError => e
     ChatwootExceptionTracker.new(e).capture_exception
   end
 end
+
+ChatwootHub.singleton_class.prepend_mod_with('ChatwootHub')