feat: allow SP initiated SAML (#12447)

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

config/locales/en.yml

@@ -36,6 +36,10 @@ en:
       success: 'Channel reauthorized successfully'
       not_required: 'Reauthorization is not required for this inbox'
       invalid_channel: 'Invalid channel type for reauthorization'
+  auth:
+    saml:
+      invalid_email: 'Please enter a valid email address'
+      authentication_failed: 'Authentication failed. Please check your credentials and try again.'
   messages:
     reset_password_success: Woot! Request for password reset is successful. Check your mail for instructions.
     reset_password_failure: Uh ho! We could not find any user with the specified email.

config/routes.rb

@@ -325,6 +325,9 @@ Rails.application.routes.draw do
         resources :webhooks, only: [:create]
       end
 
+      # Frontend API endpoint to trigger SAML authentication flow
+      post 'auth/saml_login', to: 'auth#saml_login'
+
       resource :profile, only: [:show, :update] do
         delete :avatar, on: :collection
         member do