Does Su Song's 1092 water-driven astronomical clock tower count as the first mechanical clock, or does that title belong to the weight-driven verge-escapement clocks first attested in Europe in the 1280s?

The two traditions used different power sources, a water clock feeding an escapement-like linkwork versus a purely weight-and-spring drive train, so the answer turns on which feature defines "mechanical clock," not on a missing fact.