fix(tests): align auth tests with NotAuthenticatedError and 302 redirect

The auth dependency raises NotAuthenticatedError (not HTTPException),
and the exception handler returns a 302 redirect. Updated the unit test
to expect NotAuthenticatedError, and all route auth tests to accept 302
alongside 401/303.

tests/test_dashboard_routes.py

@@ -9,7 +9,7 @@ class TestDashboard:
     def test_dashboard_requires_auth(self, client: TestClient) -> None:
         """GET /dashboard should require admin login."""
         response = client.get("/dashboard", follow_redirects=False)
-        assert response.status_code in (401, 303)
+        assert response.status_code in (401, 302, 303)
 
 
 class TestExerciseProgress:
@@ -18,4 +18,4 @@ class TestExerciseProgress:
     def test_exercise_progress_requires_auth(self, client: TestClient) -> None:
         """GET /dashboard/exercise/1 should require admin login."""
         response = client.get("/dashboard/exercise/1", follow_redirects=False)
-        assert response.status_code in (401, 303)
+        assert response.status_code in (401, 302, 303)