Merge 'main' into komasolver fork

.docker/extra_requirements.txt

.gitlab-ci.yml

AKDashboard/tests.py

AKModel/locale/de_DE/LC_MESSAGES/django.po

AKModel/migrations/0063_field_validators.py

AKModel/migrations/0064_merge_20250304_1416.py

AKModel/models.py

AKPlan/views.py

AKScheduling/locale/de_DE/LC_MESSAGES/django.po

AKSubmission/api.py

AKSubmission/locale/de_DE/LC_MESSAGES/django.po

AKSubmission/tests.py

AKSubmission/views.py

INSTALL.md

Utils/check.sh

Utils/setup.sh

Utils/test.sh

requirements.txt