feat: Bulk actions for contacts (#12763)

Introduces APIs and UI for bulk actions in contacts table. The initial
action available will be assign labels

Fixes: #8536 #12253 

## Screens

<img width="1350" height="747" alt="Screenshot 2025-10-29 at 4 05 08 PM"
src="https://github.com/user-attachments/assets/0792dff5-0371-4b2e-bdfb-cd32db773402"
/>
<img width="1345" height="717" alt="Screenshot 2025-10-29 at 4 05 19 PM"
src="https://github.com/user-attachments/assets/ae510404-c6de-4c15-a720-f6d10cdac25b"
/>

---------

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

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

@@ -1,13 +1,11 @@
 class Api::V1::Accounts::BulkActionsController < Api::V1::Accounts::BaseController
-  before_action :type_matches?
-
   def create
-    if type_matches?
-      ::BulkActionsJob.perform_later(
-        account: @current_account,
-        user: current_user,
-        params: permitted_params
-      )
+    case normalized_type
+    when 'Conversation'
+      enqueue_conversation_job
+      head :ok
+    when 'Contact'
+      enqueue_contact_job
       head :ok
     else
       render json: { success: false }, status: :unprocessable_entity
@@ -16,11 +14,34 @@ class Api::V1::Accounts::BulkActionsController < Api::V1::Accounts::BaseControll
 
   private
 
-  def type_matches?
-    ['Conversation'].include?(params[:type])
+  def normalized_type
+    params[:type].to_s.camelize
   end
 
-  def permitted_params
+  def enqueue_conversation_job
+    ::BulkActionsJob.perform_later(
+      account: @current_account,
+      user: current_user,
+      params: conversation_params
+    )
+  end
+
+  def enqueue_contact_job
+    Contacts::BulkActionJob.perform_later(
+      @current_account.id,
+      current_user.id,
+      contact_params
+    )
+  end
+
+  def conversation_params
     params.permit(:type, :snoozed_until, ids: [], fields: [:status, :assignee_id, :team_id], labels: [add: [], remove: []])
   end
+
+  def contact_params
+    params.require(:ids)
+    permitted = params.permit(:type, ids: [], labels: [add: []])
+    permitted[:ids] = permitted[:ids].map(&:to_i) if permitted[:ids].present?
+    permitted
+  end
 end