Add a signing script to test the UI

scripts/sign-tx.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env -S nix shell nixpkgs#jq .#cardano-cli .#cardano-address -c bash
+# shellcheck shell=bash
+
+set -euo pipefail
+
+if [ "$#" -ne 2 ]; then
+    echo "Usage: $0 <mnemonic> <unsigned-tx-json>" >&2
+    exit 1
+fi
+
+temp_dir=$(mktemp -d)
+
+# cleanup function
+cleanup() {
+    rm -rf "$temp_dir"
+}
+
+trap cleanup EXIT
+trap cleanup ERR
+trap cleanup SIGINT
+
+# collect arguments
+mnemonic=$1
+unsigned=$2
+
+# create the root key
+cardano-address key from-recovery-phrase Shelley <<<"$mnemonic" >"$temp_dir/root.xsk"
+
+# extract bip32 paths from the unsigned tx json
+paths=$(jq -r '.bip32Paths[]' <<<"$unsigned")
+
+# derive keys, convert to cardano-cli format and collect --signing-key-file arguments
+index=0
+signing_key_files=""
+for path in $paths; do
+    key_file="$temp_dir/key${index}.xsk"
+    cardano-address key child "$path" <"$temp_dir/root.xsk" >"$key_file"
+    cli_key_file="$temp_dir/key${index}.skey"
+    cardano-cli key convert-cardano-address-key \
+        --shelley-payment-key \
+        --signing-key-file "$key_file" \
+        --out-file "$cli_key_file"
+    signing_key_files="$signing_key_files --signing-key-file $temp_dir/key${index}.skey"
+    index=$((index + 1))
+done
+
+# dump unsigned tx to a file
+echo "$unsigned" >"$temp_dir/tx.unsigned"
+
+# sign the transaction
+# shellcheck disable=SC2086
+cardano-cli conway transaction sign \
+    $signing_key_files \
+    --tx-body-file "$temp_dir/tx.unsigned" \
+    --out-file "$temp_dir/tx.signed" \
+    --testnet-magic 1
+
+# print the signed transaction
+cat "$temp_dir/tx.signed"