onnxruntime

e27c1edf - Prevent cross-EP Cast fusion in RemoveDuplicateCastTransformer (#27363)

Prevent cross-EP Cast fusion in RemoveDuplicateCastTransformer (#27363) ### Description Fixes an incorrect Cast deduplication across execution provider boundaries. Today, `Cast(int64->float, CPU) -> Cast(float->float16, WebGPU)` can be fused into `Cast(int64->float16, WebGPU)`, which is invalid for WebGPU and can fail kernel lookup. This change adds an EP check so Cast fusion only happens when both nodes are on the same EP, and adds a regression test for this scenario. ### Motivation and Context Fixes #27291