Desktop Auto Nest, Console --autonest, MCP autonest_plate and the API
NestRunner all run through NestPipeline, so nothing calls the old
orchestration any more.
Delete MultiPlateNester (with MultiPlateNestOptions, MultiPlateResult,
PlateResult, PartClass and PartSortOrder), PlateOptimizer and
PlateOptimizerResult, plus their tests. The explicit-strategy contract
those tests checked now lives at PlateFillService.ResolveStrategy, which
keeps its null-means-Default, canonical-name and unknown-name tests.
CreateFiller loses its internal visibility, which only the deleted
orchestrators used.
This breaks source and binary compatibility for external callers of the
removed types; whole-job callers use NestPipeline.Run or INestingEngine.