Define Gaudi backend scope

[ehartford]

Define the initial QuixiCore Gaudi backend scope.

Platform:

• Intel Gaudi2-3 / HPU / SynapseAI / TPC

Initial targets:

• gaudi2
• gaudi3

Repository:

• QuixiAI/quixicore-gaudi

Note:

• Gaudi remains separate from XPU because it uses a distinct HPU/SynapseAI/TPC ecosystem.