You needn't use the PHP module, using PHP in the backend UI is usually a bad idea anyway.
First of all, the node creation link is simply a system link like
/node/add/project which works only for users with the correct permissions.
There are ways to correctly route links through Drupal in Views (custom text—output as link), but as this is just for administrative reasons, you can probably simplay paste HTML like
<a href="/node/add/project">add Project</a> in a custom text field / View header / View footer.
This displays the link for everyone with access to the View though.
If you want to display the link to specific users only, the easiest way is to simply create a block with the aforementioned link, display it on the same page as the View and show it only on specific user roles.
You could also set up a different view with different access privileges and attach it via an additional module, but I would deem this overkill.