The inventory page gets a "Ny vare" link and a "Rediger" link per product,
leading to a form for name, prices, volume, alcohol, description and whether
the product is for sale. Stock still changes only through inventory
transactions and sales, and the image through the admin.
Saving needs the same access as the Django admin: staff, plus the add or
change product permission (superusers have both). The server checks this on
every save and validates with the model's rules. Logged out visitors are
sent to log in and back to the form.
New in the API: createProduct and updateProduct mutations, a product query,
and a me query so the frontend knows who is logged in.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>