So you got the shipping confirmation for your order? You should get the code after getting the shipping notice but I guess they're still rolling out...
And the worst thing Is Google silence.
Official support channels (chat or phone) are unavailable.
No updates on Twitter
No updates on this forum
Same here. What a waste.
From what I've seen, those who have contacted Stadia support are sharing it may take 3-5 business days and to contact support if you still haven't received the code by the end of the week.