refactor(auth): improve code structure and add user registration endpoint

refactor(main): update index route response and remove greeting service

refactor(decorators): streamline authentication decorators and remove unused ones

test(routes): update tests to reflect changes in main routes and error messages

tests/test_routes.py

@@ -21,19 +21,7 @@ class TestMainRoutes:
         """Test the index route."""
         response = client.get("/api/")
         assert response.status_code == 200
-        assert response.get_json() == {"message": "Hello from backend!"}
-
-    def test_hello_route_without_name(self, client) -> None:
-        """Test hello route without name parameter."""
-        response = client.get("/api/hello")
-        assert response.status_code == 200
-        assert response.get_json() == {"message": "Hello from backend!"}
-
-    def test_hello_route_with_name(self, client) -> None:
-        """Test hello route with name parameter."""
-        response = client.get("/api/hello/Alice")
-        assert response.status_code == 200
-        assert response.get_json() == {"message": "Hello, Alice!"}
+        assert response.get_json() == {"message": "API is running", "status": "ok"}
 
     def test_health_route(self, client) -> None:
         """Test health check route."""
@@ -46,4 +34,4 @@ class TestMainRoutes:
         response = client.get("/api/protected")
         assert response.status_code == 401
         data = response.get_json()
-        assert data["error"] == "Authentication required"
+        assert data["error"] == "Authentication required (JWT or API token)"