PersistenceInChunksContext

Thin Simplex-specific wrapper around CellularPersistenceInChunksContext, exactly mirroring SimplicialHomologyContext's relationship to CellularHomologyContext above -- every existing call site (PersistenceInChunksContext[Int, Double](...) etc.) keeps working unchanged, since the generic engine itself has no Simplex-specific behavior anywhere in its body: everything goes through the generic OrderedCell interface (.dim, .boundary[CoefficientT]), so genericizing was a pure type-annotation change, not a behavior change. Simplex[VertexT] is OrderedCell resolves automatically here from Ordering[VertexT] alone (defaultSimplexIsOrderedCell, SimplexOrderedCell.scala), same as SimplicialHomologyContext already relies on. See .claude/WORKLOG-simplicial-set-filtration.md.