feat: APIs to assign agents_bots as assignee in conversations (#12836)

## Summary
- add an assignee_agent_bot_id column as an initital step to prototype
this before fully switching to polymorphic assignee
- update assignment APIs and conversation list / show endpoints to
reflect assignee as agent bot
- ensure webhook payloads contains agent bot assignee


[Codex
Task](https://chatgpt.com/codex/tasks/task_e_6912833377e48326b6641b9eee32d50f)

---------

Co-authored-by: Pranav <pranav@chatwoot.com>

app/controllers/api/v1/accounts/agent_bots_controller.rb

@@ -4,7 +4,7 @@ class Api::V1::Accounts::AgentBotsController < Api::V1::Accounts::BaseController
   before_action :agent_bot, except: [:index, :create]
 
   def index
-    @agent_bots = AgentBot.where(account_id: [nil, Current.account.id])
+    @agent_bots = AgentBot.accessible_to(Current.account)
   end
 
   def show; end
@@ -37,7 +37,7 @@ class Api::V1::Accounts::AgentBotsController < Api::V1::Accounts::BaseController
   private
 
   def agent_bot
-    @agent_bot = AgentBot.where(account_id: [nil, Current.account.id]).find(params[:id]) if params[:action] == 'show'
+    @agent_bot = AgentBot.accessible_to(Current.account).find(params[:id]) if params[:action] == 'show'
     @agent_bot ||= Current.account.agent_bots.find(params[:id])
   end
 

app/controllers/api/v1/accounts/conversations/assignments_controller.rb

@@ -1,7 +1,7 @@
 class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Accounts::Conversations::BaseController
   # assigns agent/team to a conversation
   def create
-    if params.key?(:assignee_id)
+    if params.key?(:assignee_id) || agent_bot_assignment?
       set_agent
     elsif params.key?(:team_id)
       set_team
@@ -13,17 +13,23 @@ class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Account
   private
 
   def set_agent
-    @agent = Current.account.users.find_by(id: params[:assignee_id])
-    @conversation.assignee = @agent
-    @conversation.save!
-    render_agent
+    resource = Conversations::AssignmentService.new(
+      conversation: @conversation,
+      assignee_id: params[:assignee_id],
+      assignee_type: params[:assignee_type]
+    ).perform
+
+    render_agent(resource)
   end
 
-  def render_agent
-    if @agent.nil?
-      render json: nil
+  def render_agent(resource)
+    case resource
+    when User
+      render partial: 'api/v1/models/agent', formats: [:json], locals: { resource: resource }
+    when AgentBot
+      render partial: 'api/v1/models/agent_bot_slim', formats: [:json], locals: { resource: resource }
     else
-      render partial: 'api/v1/models/agent', formats: [:json], locals: { resource: @agent }
+      render json: nil
     end
   end
 
@@ -32,4 +38,8 @@ class Api::V1::Accounts::Conversations::AssignmentsController < Api::V1::Account
     @conversation.update!(team: @team)
     render json: @team
   end
+
+  def agent_bot_assignment?
+    params[:assignee_type].to_s == 'AgentBot'
+  end
 end

app/controllers/concerns/ensure_current_account_helper.rb

@@ -25,6 +25,9 @@ module EnsureCurrentAccountHelper
   end
 
   def account_accessible_for_bot?(account)
-    render_unauthorized('Bot is not authorized to access this account') unless @resource.agent_bot_inboxes.find_by(account_id: account.id)
+    return if @resource.account_id == account.id
+    return if @resource.agent_bot_inboxes.find_by(account_id: account.id)
+
+    render_unauthorized('Bot is not authorized to access this account')
   end
 end