fix(configure): list postmark under supported transports

The postmark transport was already implemented but missing from the
configure command, so it could not be selected during setup nor did it
generate the corresponding config block and env variables.

Author: thetutlage

configure.ts

@@ -26,6 +26,7 @@ const ENV_VARIABLES: Record<string, Record<string, string | number>> = {
   sparkpost: { SPARKPOST_API_KEY: 'your-sparkpost-api-key' },
   resend: { RESEND_API_KEY: 'your-resend-api-key' },
   brevo: { BREVO_API_KEY: 'your-brevo-api-key' },
+  postmark: { POSTMARK_API_KEY: 'your-postmark-api-key' },
 }
 
 /**

stubs/config/mail.stub

@@ -79,6 +79,11 @@ const mailConfig = defineConfig({
       key: env.get('RESEND_API_KEY'),
       baseUrl: 'https://api.resend.com',
     }),
+    {{/if}} {{#if transports.includes('postmark')}}
+    postmark: transports.postmark({
+      key: env.get('POSTMARK_API_KEY'),
+      baseUrl: 'https://api.postmarkapp.com',
+    }),
     {{/if}}
   },
 })