test: add test suite with 65 tests, 73% coverage

- Unit tests: password hashing, notification providers, webhook field parsing
- Integration tests: auth routes (register/login/confirm-email/logout),
  invite flow, Evotor webhooks (/user/create, /user/verify, /user/token),
  admin panel (access control, activate/suspend/delete/reset-password)
- conftest: SQLite in-memory engine, transactional sessions, factory-boy
  factories (UserFactory with UserRoleEnum variants)
- Fix bcrypt: replace passlib (broken on Python 3.14 + bcrypt 5.x) with
  direct bcrypt calls; drop passlib from requirements.txt
- Fix datetime.utcnow() deprecation across routes and tests
- Fix Jinja2 TemplateResponse signature (request as first positional arg)
- Add coverage config to pyproject.toml

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

requirements.txt

@@ -6,8 +6,7 @@ sqlalchemy==2.0.36
 alembic==1.14.0
 pymysql==1.1.1
 cryptography>=44.0.0
-passlib[bcrypt]==1.7.4
-bcrypt==4.2.1
+bcrypt>=4.2.1
 pydantic-settings==2.6.1
 httpx==0.28.1
 celery[redis]==5.4.0