Contract Time is established in A201 Article 8 and refers to the contract for construction:
"Unless otherwise provided, Contract Time is the period of time, including authorized adjustments, allotted in the Contract Documents for Substantial Completion of the Work.
Project Duration, on the other hand, is not a term defined in the AIA contracts. It’s commonly used to refer to the architect’s scope of services. This term can depend on the context in which it is used.