feat: Refactor path handling for data directories and enhance test setup with user-specific image management

backend/tests/conftest.py

@@ -1,6 +1,11 @@
 import os
+os.environ['DB_ENV'] = 'test'
+import sys
 import pytest
 
+# Ensure backend root is in sys.path for imports like 'config.paths'
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
 @pytest.fixture(scope="session", autouse=True)
 def set_test_db_env():
     os.environ['DB_ENV'] = 'test'