Adding a project manager no longer saves the project

Fixed a form submission bug where adding a contact would accidentally submit the entire project.

Bug Fixes

The create-contact sheet was nested in the project creation form's React tree. When you clicked the submit button to add a contact, the form submission event bubbled up and accidentally submitted the parent project form — saving the entire project prematurely.

Now the contact form properly stops event propagation, so adding a PM is isolated to that action and doesn't trigger the project save.