feat(conversations): add message creation limit lock

lib/custom_exceptions/conversation_message_creation_locked.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class CustomExceptions::ConversationMessageCreationLocked < CustomExceptions::Base
+  ERROR_CODE = 'conversation_message_creation_locked'
+
+  def message
+    if lock_state[:message_creation_lock_reason] == 'message_limit'
+      "This conversation has reached the #{lock_state[:message_limit]} message limit. We will drop all messages after this limit."
+    else
+      'This conversation is locked. We will drop all new messages until it is unlocked.'
+    end
+  end
+
+  def http_status
+    :unprocessable_entity
+  end
+
+  def to_hash
+    {
+      error: message,
+      message: message,
+      error_code: ERROR_CODE,
+      **lock_state
+    }
+  end
+
+  private
+
+  def lock_state
+    @lock_state ||= @data.message_creation_lock_state
+  end
+end