Growth

Whether this rule's replacement is smaller, the same size, or larger than its pattern.
Computed exactly from NodeCount where the replacement is a
pattern; declared, not derived, where it is code, the same way
Soundness is declared rather than derived — a code-built replacement has no
pattern tree to count nodes on, so the only source of truth is whoever wrote the rule and
can justify the claim. Undeclared code-built rules stay Unknown,
which is the honest default: not proven safe is not the same as safe.