Implement backend method to send email notifications when screen recordings
are ready for download. Enables users to be alerted when their recordings are
available. Frontend implementation to follow in upcoming commits.
This service is triggered by the storage hook from Minio.
Add minimal unit test coverage for notification service, addressing previous
lack of tests in this area. The notification service was responsible for
calling the unstable summary service feature, which was developped way too
quickly.
The email template has been reviewed by a LLM, to make it user-friendly and
crystal clear.
b7d964db56