feat: Add APIs to manage custom roles in Chatwoot (#9995)

Co-authored-by: Pranav <pranavrajs@gmail.com>

enterprise/app/models/custom_role.rb

@@ -0,0 +1,42 @@
+# == Schema Information
+#
+# Table name: custom_roles
+#
+#  id          :bigint           not null, primary key
+#  description :string
+#  name        :string
+#  permissions :text             default([]), is an Array
+#  created_at  :datetime         not null
+#  updated_at  :datetime         not null
+#  account_id  :bigint           not null
+#
+# Indexes
+#
+#  index_custom_roles_on_account_id  (account_id)
+#
+#
+
+# Available permissions for custom roles:
+# - 'conversation_manage': Can manage all conversations.
+# - 'conversation_unassigned_manage': Can manage unassigned conversations and assign to self.
+# - 'conversation_participating_manage': Can manage conversations they are participating in (assigned to or a participant).
+# - 'contact_manage': Can manage contacts.
+# - 'report_manage': Can manage reports.
+# - 'knowledge_base_manage': Can manage knowledge base portals.
+
+class CustomRole < ApplicationRecord
+  belongs_to :account
+  has_many :account_users, dependent: :nullify
+
+  PERMISSIONS = %w[
+    conversation_manage
+    conversation_unassigned_manage
+    conversation_participating_manage
+    contact_manage
+    report_manage
+    knowledge_base_manage
+  ].freeze
+
+  validates :name, presence: true
+  validates :permissions, inclusion: { in: PERMISSIONS }
+end