fix: read back sent copies after the sec 5.6 upstream fix, pinned at 2d65d66

lib/smol/ui.dart

@@ -0,0 +1,24 @@
+// Display helpers for the keys and ids the native library hands back as
+// base32 and hex — formatting only, no protocol meaning.
+
+import "dart:typed_data";
+
+/// Lowercase hex, as the message ids cross the ABI.
+String hex(List<int> bytes) =>
+    bytes.map((b) => b.toRadixString(16).padLeft(2, "0")).join();
+
+/// The compact human check for a key: the first 20 base32 characters in
+/// groups of four, the same shape every smol client shows.
+String fingerprint(String keyB32) {
+  final s = keyB32.substring(0, 20);
+  return RegExp(".{4}").allMatches(s).map((m) => m[0]).join(" ");
+}
+
+/// The inverse of [hex]; throws on anything that is not even-length hex.
+Uint8List unhex(String text) {
+  if (text.length % 2 != 0) {
+    throw FormatException("odd-length hex string");
+  }
+  return Uint8List.fromList(
+      [for (var i = 0; i < text.length; i += 2) int.parse(text.substring(i, i + 2), radix: 16)]);
+}