feat: notify configured recipients when something is booked

config/packages/messenger.yaml

@@ -18,7 +18,13 @@ framework:
             messenger.bus.default: []
 
         routing:
-            Symfony\Component\Mailer\Messenger\SendEmailMessage: async
+            # Mail is deliberately NOT routed to async. Nothing starts a worker on the server --
+            # deploy.php only stops them -- so a queued SendEmailMessage would be written to
+            # messenger_messages and stay there, with no error anywhere and nobody notified.
+            # Sending happens in the request instead; BookingNotifier catches a transport
+            # failure so it can never fail the booking that triggered it. Route it back here
+            # once a `messenger:consume async` worker actually runs.
+            # Symfony\Component\Mailer\Messenger\SendEmailMessage: async
             Symfony\Component\Notifier\Message\ChatMessage: async
             Symfony\Component\Notifier\Message\SmsMessage: async
 

config/packages/twig.yaml

@@ -2,6 +2,10 @@ twig:
     file_name_pattern: '*.twig'
     # One theme for the whole app, so it is registered globally rather than per-template.
     form_themes: ['forms.html.twig']
+    paths:
+        # Mail templates embed the logo with email.image('@images/logo.png'), which needs the file
+        # on a Twig path -- an asset URL would be a remote image most clients block.
+        '%kernel.project_dir%/assets/images': images
 
 when@test:
     twig:

config/services.yaml

@@ -26,6 +26,12 @@ services:
         arguments:
             $logger: '@monolog.logger.audit'
 
+    # Booking notifications. The sender is also the To of every notification -- the actual
+    # recipients are Bcc'd -- so it has to be an address that may both send and receive.
+    App\Service\BookingNotifier:
+        arguments:
+            $sender: '%env(string:MAILER_FROM)%'
+
     # The myep OAuth2 client. Endpoint URLs are configuration rather than constants (same as
     # myep-team), so dev, staging and production differ by .env alone. Empty credentials are a
     # valid state: the login page then says the client is not registered yet instead of bouncing