fix(ci): run tests from project root with correct PYTHONPATH

.gitea/workflows/ci-cd.yml

@@ -78,8 +78,8 @@ jobs:
         run: |
           export PATH="$HOME/.local/bin:$PATH"
           source .venv/bin/activate
-          cd src
-          python manage.py test --verbosity=2
+          export PYTHONPATH="${PWD}/src:${PYTHONPATH}"
+          python src/manage.py test tests --verbosity=2
         env:
           DJANGO_SETTINGS_MODULE: config.settings.test
           SECRET_KEY: test-secret-key-for-ci