Cardano ledger operations compiled to wasm32-wasi.

Extracted from cardano-ledger-inspector as a standalone home for the wasm toolchain and the ledger kernel.

Bootstrap in progress (epic #84 / W0). The buildable skeleton lands via the feat/wasm-skeleton PR.

nix build            # produces the wasm32-wasi artifact from the stub
nix flake check      # runs the flake checks
nix develop -c just ci   # local CI gate (once the skeleton lands)

MIT — see LICENSE.