sim-expr-tree-core

Backend-neutral finite namespace records for expression-tree storage. The crate defines stable tree, directory, and cell identities; durable source and stamp records; field-wise inherited source/result codec policy and hard-clamped face budgets; and serialized generated-name reservation over canonical sim-table-core path names.

The storage model keeps authored source, operational control, and rebuildable derived state in separate lanes while composing explicit Table and Dir mounts. The calculation crate adapts the derived lane to an ordinary Table, allowing each selected backend to retain its own durability and transaction behavior.