- Rewrote test_incremental_update.cpp to match new API (FeatureHistory param) - Fixed invalidate_cache to propagate dirty flag to downstream nodes via mark_dirty - 15/15 tests pass on Linux build
- IncrementalUpdateEngine: dirty propagation, topological rebuild, cache hit/miss - InstanceCache: shared LOD mesh for identical parts - LargeAssemblyManager: BVH spatial index, view frustum culling, assembly stats - format_io: auto-detect STEP/IGES, batch import with error recovery - 31 tests: incremental (11), large assembly (12), format IO (8)