Fix failing tests (#1009)

* chore: ignore all .data directories

* fix: date locale for unit tests

* test: disable parallelism to prevent database locks

* chore: fix lint errors

* chore: remove unused function

---------

Co-authored-by: zebrapurring <>
Co-authored-by: Tonya <tonya@tokia.dev>

.gitignore

@@ -60,7 +60,7 @@ backend/app/api/static/public/*
 backend/api
 
 docs/.vitepress/cache/
-/.data/
+.data/
 
 # Playwright
 frontend/test-results/