AMR Roadmap

I think it's good to have a AMR roadmap for the various open topics left. The ordering is driven by dependencies and API instead of importance. Happy to discuss and reorder. (Already discussed with the lazy guy @claude)

Roadmap

1. #1413 — ForestBWG as the grid (lazy materialization facade, drop NonConformingGrid) First because every later item touches the boundary it reshapes: where conformity_info lives, what materialization emits, and the cell-numbering lifecycle / reclose!. Landing it last would mean building those against NonConformingGrid + explicit creategrid and churning them afterwards. It's also the smallest of the five.
2. #1411 — Transient adaptivity: old-to-new cell id map and solution transfer Biggest user-facing unlock (time-dependent problems), and deliberately scoped to linear Lagrange, so it needs nothing from #1409/#1410. It composes naturally with the facade: the epoch bump in refine!/coarsen! is exactly the moment to emit the old-to-new map, and reclose! is its natural consumer.
3. #1410 — Curved geometry (higher-order geometry interpolation of the macro mesh) Before #1409 because the degree-scaled node lattice and degree-parametric Lnodes materialization built here are shared infrastructure: once node identity lives on the [0, n·2^b] lattice, the entity-dof bookkeeping that higher-order conformity constraints need largely falls out of the same element-node matrix. (At least if we go the full Lnodes path)
4. #1409 — Conformity constraints beyond linear Lagrange
5. #1455 — Generalized Morton SFC (simplices, wedges, general element types) Last regardless of the rest of the ordering: it reshapes the Morton core itself, so anything in flight when it lands would need rework. Everything above is hypercube-only by design.

Notes

• #1410 + #1409 together are what deliver sub-/iso-/super-parametric adaptivity — geometry order and field order are decoupled, so they're two halves of one capability with no cross-terms.
• The other open issues with the AMR tag are more "convenience" issues and aren't blocking any of the above.