fix(auth-service): log all email delivery paths

The first pass updated only the client-branded delivery log and overlooked the three other sendMail call sites. That left standard sign-in, welcome, and backup verification deliveries without the same structured recipient context.\n\nAdd an email field to the delivery log for every sendMail path while retaining Nodemailer's required to envelope property.\n\nCo-authored-by: OpenAI Codex <codex@openai.com>

Author: aspiers

.changeset/email-log-recipient-field.md

@@ -6,4 +6,4 @@ Email delivery logs use a consistent recipient field.
 
 **Affects:** Operators
 
-**Operators:** Update structured-log queries for `Sent client-branded OTP email` to read the recipient from `email` instead of `to`.
+**Operators:** All four email delivery paths now log the recipient as `email`: client-branded OTP, standard sign-in OTP, welcome OTP, and backup-email verification. Update structured-log queries for `Sent client-branded OTP email` to read `email` instead of `to`.

packages/auth-service/src/email/sender.ts

@@ -165,6 +165,7 @@ export class EmailSender {
       text,
       html,
     })
+    logger.info({ email: to }, 'Sent sign-in OTP email')
   }
 
   private async sendWelcomeCode(opts: {
@@ -183,6 +184,7 @@ export class EmailSender {
       text,
       html,
     })
+    logger.info({ email: to }, 'Sent welcome OTP email')
   }
 
   async sendBackupEmailVerification(opts: {
@@ -201,5 +203,6 @@ export class EmailSender {
       text,
       html,
     })
+    logger.info({ email: to }, 'Sent backup email verification')
   }
 }