registeredClass.style = 32_769;
Don't use an integer like that, stick with bit wise ors.
LPCWSTR classname = toUTF16z(name);
GC owned memory, that could result in surprises.
const LPWSTR windowname = toUTF16z(title);
Ditto
I'm not sure your window callback procedure is right.
For instance you are not calling DefWindowProc, and you are not handling
WM_PAINT in any form.
But one other thing, your approach to the event loop is going to come
back to bite you at some point. Windows is based around a push event
loop model, not a pull like other system Windowing libraries (such as
X11). It can get recursive. I learned this one the hard way.
