MaterialX Graph Editor pin preview to node

[HardCoreCodin]

Support pinning the preview render to a specific node in the graph to always preview its result, even as choosing and interacting with other nodes in the graph.

[MatthieuBEAUD]

Hello, I'd like to take a look at this for the september 2026 dev days. It that possible ?

[jstone-lucasfilm]

Welcome, @MatthieuBEAUD, and I've assigned it to you!