7943b123ae
The three cost nodes (ConstantCost, CarryCost, VolSlippageCost) shared a byte-identical generic doc line, so `aura graph introspect --vocabulary` could not tell them apart — C29's per-entry meaning was formally met but not entry-specific (binary-only M1 fieldtest finding). cost_node_builder now takes the factor-specific one-line doc as a parameter (the shared string is gone from the single schema home); each builder states its own charge basis. RED-first: cost_node_descriptions_are_pairwise_distinct failed against the shared string before the fix. closes #330