feat: Improve Captain interactions, activity messages (#11493)

Show captain messages under the name of the assistant which generated
the message.

- Add support for `Captain::Assistant` sender type
- Add push_event_data for captain_assistants
- Add activity message handler for captain_assistants
- Update UI to show captain messages under the name of the assistant
- Fix the issue where openAI errors when image is sent
- Add support for custom name of the assistant

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

enterprise/app/models/captain/assistant.rb

@@ -15,6 +15,8 @@
 #  index_captain_assistants_on_account_id  (account_id)
 #
 class Captain::Assistant < ApplicationRecord
+  include Avatarable
+
   self.table_name = 'captain_assistants'
 
   belongs_to :account
@@ -26,6 +28,7 @@ class Captain::Assistant < ApplicationRecord
            dependent: :destroy_async
   has_many :inboxes,
            through: :captain_inboxes
+  has_many :messages, as: :sender, dependent: :nullify
 
   validates :name, presence: true
   validates :description, presence: true
@@ -34,4 +37,32 @@ class Captain::Assistant < ApplicationRecord
   scope :ordered, -> { order(created_at: :desc) }
 
   scope :for_account, ->(account_id) { where(account_id: account_id) }
+
+  def push_event_data
+    {
+      id: id,
+      name: name,
+      avatar_url: avatar_url.presence || default_avatar_url,
+      description: description,
+      created_at: created_at,
+      type: 'captain_assistant'
+    }
+  end
+
+  def webhook_data
+    {
+      id: id,
+      name: name,
+      avatar_url: avatar_url.presence || default_avatar_url,
+      description: description,
+      created_at: created_at,
+      type: 'captain_assistant'
+    }
+  end
+
+  private
+
+  def default_avatar_url
+    "#{ENV.fetch('FRONTEND_URL', nil)}/assets/images/dashboard/captain/logo.svg"
+  end
 end