Question: should BN254 host functions also expose Go-side wrappers, or follow the BLS12-381 precedent of staying VM-internal?

## Context

This is the wasmvm-side companion to [CosmWasm/cosmwasm#2685](https://github.com/CosmWasm/cosmwasm/issues/2685) — a proposal to add BN254 (alt_bn128) host functions to CosmWasm, motivated by Juno governance proposal [#374](https://ping.pub/juno/gov/374) (passed 2026-05-05, ~80% Yes / 22% Abstain / 0.003% No-with-Veto).

The cosmwasm-side issue covers the host-function ABI, the Rust crate, the gas schedule, and the **measured 1.823× gas reduction** (370,600 → 203,266 SDK gas per Groth16 verification, 5 samples σ = 0). The patches there target three cosmwasm tags in parallel — v2.2.2 (audit baseline), v2.2.7 (latest 2.2.x), and **v3.0.6** (latest v3) — all 10/10 CLEAN.

**This wasmvm-side issue is now smaller in scope than originally drafted.** When we tried to author Go-side wrappers (mirroring the BLS12-381 pattern we expected), the patches failed because **BLS12-381 itself has no Go-side wrappers in either `wasmvm` v2.2.4 or `wasmvm` v3.0.4**. We dropped the wrapper patches and would like to confirm that this absence is intentional design before deciding whether to contribute the wrappers ourselves.

## The single question

Is the absence of Go-side wrappers for BLS12-381 (and by extension, BN254) **intentional design** — i.e. "these primitives are for use by Wasm contracts via host-function imports only, never by direct Go callers in `x/wasm`-adjacent code" — or is it a not-yet-done that you'd accept a contribution for?

We're happy with either answer:

- **"Intentional, leave it out":** then the BN254 work is **cosmwasm-only**. Issue 1 is the entire upstream surface and this issue closes once that's confirmed.
- **"Not-yet-done, contribution welcome":** then we'd open a follow-up wasmvm PR with the BLS12-381 + BN254 Go wrappers in one symmetrical change. The Go-side surface for BN254 alone would look like:

```go
// internal/api/bn254.go (new)
func Bn254Add(a, b []byte) ([]byte, error) { ... }
func Bn254ScalarMul(point, scalar []byte) ([]byte, error) { ... }
func Bn254PairingEquality(input []byte) (bool, error) { ... }Test body