The multi-phase lattice fill (linear, pairs, rectangle best-fit, remainder) is
no longer meant to be the engine used by default, so it gets a name for what
it does. The registry lists it as Fill and maps the old name Default to it;
PlateFillService, PlateNesterFactory and NestJobOptions use Fill, and every
fill-strategy caller still accepts Default. Console --autonest now validates
engine names through NestingEngineRegistry.ResolveName so renamed names work.
Layouts are unchanged: Default and Fill resolve to the same fillers and the
golden layouts pass under the new name.
Move BlockCatalog's private-drawing Fill invocation (BestFitCache stabilization plus
the Default FillItem call) into PrivatePlateFill so the cutout fill can reuse it
without duplicating the cache handling. Behavior unchanged; Irregular filter 96/96.
aj