[Tails-l10n] Release schedule for Tails 7.4

Hi,

anonym will be the RM for Tails 7.4.

The current plan is:

- Wednesday, 2026-01-14: build images, start testing
- Thursday, 2026-01-15: release

Developers, please:

   - Book time for automated and manual QA during office hours,
     from Wednesday 13:00 to Thursday 11:00 (Europe/Berlin).
     If you can't, please let the RM know.

   - During these 2 days, don't push any changes to the stable
     branch.

Cheers!