Allow separate configuration of support and transactional email addresses

[Paillat-dev]

Issue Summary

Currently, Ghost uses the support email address (configured in Portal settings) as the sender for all transactional emails (e.g., signup confirmations, magic links). This design causes issues for users with strict email providers that require the sender address to match the authenticated SMTP user.

Current Behavior

• The support email address (set in Portal settings) is used as the sender (from) for all transactional emails.
• This address may differ from the mail__from configuration in config.production.json.
• Some email providers (e.g., Infomaniak) reject emails where the sender address doesn't match the authenticated SMTP user.

Desired Behavior

• Allow separate configuration of user support and transactional email addresses.
• Use the mail__from address (or a new mail__transactional_from config) for sending transactional emails.
• Retain the support email address for user-facing support communications.

Benefits

1. Improved compatibility with strict email providers.
2. Clear separation of concerns between support, newsletter, and transactional emails.
3. More flexible configuration options for self-hosted Ghost instances.

Additional Context

This issue is related to the long-standing problem of email sender configuration in Ghost, as discussed in #12802. While updates have improved the situation, this change would provide even greater flexibility for self-hosted instances.

Ghost Version

5.95.0

Node.js Version

no idea

How did you install Ghost?

docker image

Database type

MySQL 8

Code of Conduct

• [X] I agree to be friendly and polite to people in this repository

[Malay207]

I would love to contribute to this issue for Hacktoberfest! Could you please assign it to me?