fix(tidy3d): FXC-5400-fix-local-cache-race-conditions

Author: marcorudolphflex

CHANGELOG.md

@@ -42,6 +42,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed sliver polygon artifacts in 2D material subdivision by filtering polygons based on grid cell size, preventing numerical issues with large-coordinate geometries.
 - Fixed `CustomMedium` gradient calculation when field coordinates exactly align with boundaries.
 - Fixed adjoint simulation `grid_spec` to align exactly with forward simulation for correct `FieldData` adjoint source power.
+- Fixed local cache race conditions causing `FileNotFoundError`.
 
 ## [2.10.2] - 2026-01-21