refactor(email): set From at transport level instead of per-message

The /settings transport preview shows `from` inside the createTransport
JSON, but the implementation was passing it per-message via sendMail.
Switch to passing it as part of the transport config so what the
preview shows matches what is actually built — no behavioural change
for outgoing emails since nodemailer treats transport-level `from` as
the default for every sendMail call.

server/src/service/infrastructure/emailService.ts

@@ -127,6 +127,9 @@ export class EmailService implements IEmailService {
 			systemEmailRejectUnauthorized,
 		} = config;
 
+		const trimmedDisplayName = systemEmailDisplayName?.trim();
+		const from = trimmedDisplayName && systemEmailAddress ? { name: trimmedDisplayName, address: systemEmailAddress } : systemEmailAddress;
+
 		const emailConfig = {
 			host: systemEmailHost,
 			port: Number(systemEmailPort),
@@ -138,6 +141,7 @@ export class EmailService implements IEmailService {
 			name: systemEmailConnectionHost || "localhost",
 			connectionTimeout: 5000,
 			pool: systemEmailPool,
+			from,
 			tls: {
 				rejectUnauthorized: systemEmailRejectUnauthorized,
 				ignoreTLS: systemEmailIgnoreTLS,
@@ -159,13 +163,9 @@ export class EmailService implements IEmailService {
 			return false;
 		}
 
-		const trimmedDisplayName = systemEmailDisplayName?.trim();
-		const from = trimmedDisplayName && systemEmailAddress ? { name: trimmedDisplayName, address: systemEmailAddress } : systemEmailAddress;
-
 		try {
 			const info = await this.transporter.sendMail({
 				to: to,
-				from: from,
 				subject: subject,
 				html: html,
 			});