Add the controllable property to QubitUnitary in LQ. This will avoid …

…the decomposition of ctrl(LQ) and hardcode of expanded controlled matrices in the IR. LightningKokkos zero-qubit device initialization is not supported on Windows.

pennylane_lightning/core/src/simulators/lightning_kokkos/StateVectorKokkos.hpp

@@ -112,6 +112,15 @@ class StateVectorKokkos final
             }
         }
 
+#ifdef _WIN32
+        constexpr bool no_qubit_init = false;
+#else
+        constexpr bool no_qubit_init = true;
+#endif
+        PL_ABORT_IF_NOT(num_qubits || no_qubit_init,
+                        "LightningKokkos zero-qubit device initialization is "
+                        "not supported on Windows.");
+
         data_ = std::make_unique<KokkosVector>("data_", exp2(num_qubits));
         setBasisState(0U);
     };

pennylane_lightning/lightning_qubit/lightning_qubit.toml

@@ -27,7 +27,7 @@ PauliX                 = { properties = [ "invertible", "controllable", "differe
 PauliY                 = { properties = [ "invertible", "controllable", "differentiable" ] }
 PauliZ                 = { properties = [ "invertible", "controllable", "differentiable" ] }
 PhaseShift             = { properties = [ "invertible", "controllable", "differentiable" ] }
-QubitUnitary           = { properties = [ "invertible",                                  ] }
+QubitUnitary           = { properties = [ "invertible", "controllable",                  ] }
 Rot                    = { properties = [ "invertible", "controllable",                  ] }
 RX                     = { properties = [ "invertible", "controllable", "differentiable" ] }
 RY                     = { properties = [ "invertible", "controllable", "differentiable" ] }