fix: cold wallet signs for any genesis hash

cold-wallet-app/lib/screens/sign_transaction_screen.dart

@@ -238,7 +238,7 @@ class _SignTransactionScreenState extends ConsumerState<SignTransactionScreen> {
       // The one place the runtime's own naming appears, nested calls included —
       // the headlines above deliberately summarise it away.
       'Call: ${parsed.call.displayTitleChain}',
-      'Network: ${parsed.network}',
+      'Network: ${parsed.network ?? 'Unknown'}',
       'Runtime: spec ${ext.specVersion}, tx version ${ext.transactionVersion}',
       'Nonce: ${ext.nonce}',
       'Era: ${ext.era}',

cold-wallet-app/test/call_display_test.dart

@@ -133,5 +133,23 @@ void main() {
       await pumpSignScreen(tester, DebugPayloads.governanceVoteAye());
       expect(signerRow(tester).label, 'Signed by');
     });
+
+    testWidgets('an unlisted genesis hash reaches review and reads Network: Unknown', (tester) async {
+      final payload = DebugPayloads.payloadForCall(
+        const balances_pallet.Txs().transferAllowDeath(dest: account(bobId), value: oneToken).encode(),
+      );
+      // Genesis hash sits before the 32-byte block hash and the metadata None byte.
+      payload.fillRange(payload.length - 65, payload.length - 33, 0xEE);
+      await pumpSignScreen(tester, SigningRequest(signer: DebugPayloads.debugSigner, payload: payload).encode());
+
+      expect(find.text('SEND'), findsOneWidget);
+      expect(find.text('Could not read transaction'), findsNothing);
+
+      await tester.ensureVisible(find.text('ADVANCED'));
+      await tester.tap(find.text('ADVANCED'));
+      await tester.pumpAndSettle();
+      expect(find.textContaining('Network: Unknown'), findsOneWidget);
+      expect(find.textContaining('Genesis hash: 0x${'ee' * 32}'), findsOneWidget);
+    });
   });
 }

cold-wallet-app/test/transaction_signing_test.dart

@@ -26,7 +26,7 @@ void main() {
       '111111111111111111111111111111111111111111111111111111111111111100';
 
   // The same transfer as originally captured on the retired devnet (genesis 826beefb…).
-  // Regression: the signer must reject payloads for networks it does not know.
+  // The signer signs for any chain, so this decodes like any other payload.
   const retiredDevnetHex =
       '0200007416854906f03a9dff66e3270a736c44e15970ac03a638471523a03069f276ca0700e876481755010000007400000002000000826beefbe2be72645ff376f18de745ac196dc77637436090de4174180706118e5a77ae1c95817ee664cf733fafa7baa8e6244b396a54e57a5bc414b24c52800600';
 
@@ -106,12 +106,12 @@ void main() {
       expect(QuantusSigningPayload.signablePayload(payload), payload);
     });
 
-    test('retired devnet payload is rejected with unknown genesis (never signed)', () {
+    test('retired devnet payload with an unlisted genesis hash is signable', () {
       final payload = Uint8List.fromList(hex.decode(retiredDevnetHex));
-      expect(
-        () => QuantusPayloadParser.parsePayload(payload, policy: const FullCallPolicy()),
-        throwsA(isA<FormatException>().having((e) => e.message, 'message', contains('Unknown genesis hash'))),
-      );
+      final parsed = QuantusPayloadParser.parsePayload(payload, policy: const FullCallPolicy());
+      expect(parsed.network, isNull);
+      expect(parsed.call.summary?.amount, BigInt.from(100000000000));
+      expect(QuantusSigningPayload.signablePayload(payload), payload);
     });
 
     test('non-transaction bytes are rejected (never signed)', () {

quantus_sdk/lib/src/quantus_payload_parser.dart

@@ -31,8 +31,9 @@ import 'package:quantus_sdk/src/constants/app_constants.dart';
 /// Hard cap on the raw signing payload; every supported call is far below this.
 const int maxPayloadBytes = maxCallBytes;
 
-/// Networks this wallet will sign for, keyed by genesis hash (lowercase hex).
-/// A payload whose genesis hash is not listed here is rejected.
+/// Display names for known networks, keyed by genesis hash (lowercase hex).
+/// Purely informational: the signer signs for any genesis hash and shows the
+/// raw hash alongside the name when one is known.
 const Map<String, String> knownNetworks = {
   '4901bf5c57fd3f9e726af399c763de6670dbdb115a91c0237e173f16eef65e72': 'Planck',
   'a5aa9e5c84d4a3722c152295e7973c9af522f2fb1ef7db5afaa3d5f4dc8d3b4f': 'Heisenberg',
@@ -94,7 +95,9 @@ class ParsedPayload {
   final DecodedCall call;
 
   final SignedExtensions extensions;
-  final String network;
+
+  /// Display name from [knownNetworks], or null when the genesis hash is not listed.
+  final String? network;
 
   /// The raw payload bytes, so a signer can offer them for inspection.
   final Uint8List raw;
@@ -113,8 +116,8 @@ class ParsedPayload {
 class QuantusPayloadParser {
   /// Decodes a full signing payload. Throws [FormatException] on any rejection:
   /// unknown pallet/call index, an inner call that does not decode exactly,
-  /// malformed extensions, trailing bytes, metadata-mode inconsistency, or a
-  /// genesis hash not in [knownNetworks].
+  /// malformed extensions, trailing bytes, or metadata-mode inconsistency.
+  /// The genesis hash is never validated; any chain is accepted.
   static ParsedPayload parsePayload(Uint8List payload, {required CallPolicy policy}) {
     if (payload.length > maxPayloadBytes) {
       throw FormatException('Payload too large: ${payload.length} bytes');
@@ -136,12 +139,12 @@ class QuantusPayloadParser {
       throw FormatException('Metadata hash mode ${extensions.metadataMode} inconsistent with metadata hash presence');
     }
 
-    final network = knownNetworks[hex.encode(extensions.genesisHash)];
-    if (network == null) {
-      throw FormatException('Unknown genesis hash: 0x${hex.encode(extensions.genesisHash)}');
-    }
-
-    return ParsedPayload(call: call, extensions: extensions, network: network, raw: payload);
+    return ParsedPayload(
+      call: call,
+      extensions: extensions,
+      network: knownNetworks[hex.encode(extensions.genesisHash)],
+      raw: payload,
+    );
   }
 
   static T _section<T>(String section, T Function() decode) {

quantus_sdk/test/quantus_payload_parser_test.dart

@@ -14,15 +14,15 @@ import 'package:quantus_sdk/quantus_sdk.dart';
 const planckGenesisHex = '4901bf5c57fd3f9e726af399c763de6670dbdb115a91c0237e173f16eef65e72';
 
 // Call portions of the original "real world" vectors (extensions stripped); the full
-// vectors were captured on a retired devnet whose genesis hash is no longer accepted.
+// vectors were captured on a retired devnet whose genesis hash is not in [knownNetworks].
 // The reversible call is re-indexed from the retired pallet index 13 to the current 11.
 const transferCall1 = '020000ef5f320156894f0fde742921c6990bf446e82c89fae5a23e701900abcd92dfb40700282e8cd1';
 const transferCall2 = '0200007416854906f03a9dff66e3270a736c44e15970ac03a638471523a03069f276ca0700e8764817';
 const reversibleCall =
     '0b04007416854906f03a9dff66e3270a736c44e15970ac03a638471523a03069f276ca0040b0464f010000000000000000000001e093040000000000';
 
 // The two original real-world vectors, kept verbatim as regression tests: both were
-// captured on the retired devnet (genesis 826beefb…) and must now be rejected.
+// captured on the retired devnet (genesis 826beefb…), which no network table lists.
 const oldNetworkTransfer =
     '020000ef5f320156894f0fde742921c6990bf446e82c89fae5a23e701900abcd92dfb40700282e8cd185012800007400000002000000826beefbe2be72645ff376f18de745ac196dc77637436090de4174180706118e3d3e081c6e3599f8ae31d404d9f087f50c25b4e08c35712e23470a60da5799ca00';
 const oldNetworkReversible =
@@ -222,16 +222,19 @@ void main() {
       });
     });
 
-    group('rejections', () {
-      test('rejects old devnet transfer with unknown genesis (regression)', () {
-        // Proves the parser walks all the way to the genesis hash and rejects unknown networks.
+    group('genesis hash', () {
+      test('signs for any chain: an unlisted genesis hash decodes with no network name', () {
         final payload = Uint8List.fromList(hex.decode(oldNetworkTransfer));
-        expect(
-          () => QuantusPayloadParser.parsePayload(payload, policy: const FullCallPolicy()),
-          throwsRejection('Unknown genesis hash'),
-        );
+        final parsed = QuantusPayloadParser.parsePayload(payload, policy: const FullCallPolicy());
+
+        expect(parsed.network, isNull);
+        expect(hex.encode(parsed.extensions.genesisHash), startsWith('826beefb'));
+        expect(parsed.call.call, 'transfer_allow_death');
+        expect(parsed.specMatchesBundled, isFalse);
       });
+    });
 
+    group('rejections', () {
       test('rejects old devnet reversible transfer (regression)', () {
         // Rejected, but note *where*: pallet index 13 was ReversibleTransfers on the
         // retired devnet and is TechCollective on this runtime, so these bytes now