verifyPow function
void
verifyPow()
Implementation
void verifyPow() {
final x = Tensor.fromList([1, 1], [3.0]);
final loss = x.pow(2.0).sum();
loss.backward();
final grads = x.grad;
bool ok = closeEnough(grads[0], 6.0);
print("POW: ${ok ? '✅ PASS' : '❌ FAIL (Expected 6.0, got ${grads[0]})'}");
}