Add unit tests for models and services

- Implemented unit tests for the Package model, covering methods such as generateId, findById, findByName, and version management.
- Created unit tests for the Repository model, including repository creation, name validation, and retrieval methods.
- Added tests for the Session model, focusing on session creation, validation, and invalidation.
- Developed unit tests for the User model, ensuring user creation, password hashing, and retrieval methods function correctly.
- Implemented AuthService tests, validating login, token refresh, and session management.
- Added TokenService tests, covering token creation, validation, and revocation processes.

test/fixtures/pypi/demo_package/pyproject.toml

@@ -0,0 +1,23 @@
+[build-system]
+requires = ["setuptools>=61.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "stack-test-demo-package"
+version = "1.0.0"
+description = "Demo package for Stack.Gallery Registry e2e tests"
+readme = "README.md"
+requires-python = ">=3.8"
+license = {text = "MIT"}
+authors = [
+    {name = "Stack.Gallery Test", email = "test@stack.gallery"}
+]
+keywords = ["demo", "test", "stack-gallery"]
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3",
+]
+
+[tool.setuptools.packages.find]
+where = ["."]