NEAR cold signing: review and sign NEAR transactions with the ML-DSA-65 key

cold-wallet-app/analysis_options.yaml

@@ -29,3 +29,7 @@ analyzer:
     missing_return: error
     must_be_immutable: error
     asset_does_not_exist: ignore
+  exclude:
+    - build/**
+    - android/**
+    - ios/**

cold-wallet-app/lib/components/signature_qr_view.dart

@@ -0,0 +1,43 @@
+import 'dart:typed_data';
+
+import 'package:flutter/material.dart';
+import 'package:quantus_sdk/quantus_sdk.dart';
+import 'package:quantus_cold_wallet/components/ur_qr_panel.dart';
+import 'package:quantus_cold_wallet/providers/ur_qr_providers.dart';
+
+/// The screen shown once a transaction is signed: [signed] as a UR QR for
+/// the hot wallet to scan, and a Done button back to home.
+class SignatureQrView extends StatelessWidget {
+  final Uint8List signed;
+  final String instruction;
+
+  const SignatureQrView({super.key, required this.signed, required this.instruction});
+
+  @override
+  Widget build(BuildContext context) {
+    final colors = context.colorsV3;
+    final text = context.themeTextV3;
+
+    return ScaffoldBase(
+      appBar: const V2AppBar(title: 'Signature', showBackButton: false),
+      mainContent: SingleChildScrollView(
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.center,
+          children: [
+            const SizedBox(height: 8),
+            Text(
+              instruction,
+              style: text.body.copyWith(color: colors.textMuted),
+              textAlign: TextAlign.center,
+            ),
+            const SizedBox(height: 24),
+            UrQrPanel(payload: UrPayload(signed)),
+          ],
+        ),
+      ),
+      bottomContent: ScaffoldBaseBottomContent(
+        child: QuantusButton.simple(label: 'Done', onTap: () => Navigator.popUntil(context, (r) => r.isFirst)),
+      ),
+    );
+  }
+}

cold-wallet-app/lib/components/signing_refusal_view.dart

@@ -0,0 +1,80 @@
+import 'package:flutter/material.dart';
+import 'package:quantus_sdk/quantus_sdk.dart';
+
+/// Why a signing request was refused, with the one detail that identifies it
+/// (the account, the key, the decoder's message) and a way back to home.
+/// Shared by every signing screen so a refusal looks the same whatever the
+/// chain.
+class SigningRefusalView extends StatelessWidget {
+  final String appBarTitle;
+  final String title;
+  final String message;
+  final Widget detail;
+
+  const SigningRefusalView({
+    super.key,
+    required this.appBarTitle,
+    required this.title,
+    required this.message,
+    required this.detail,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final colors = context.colorsV3;
+    final text = context.themeTextV3;
+    return ScaffoldBase(
+      appBar: V2AppBar(title: appBarTitle),
+      // The detail can be as long as a decoder's message, which no layout can
+      // bound, so this column scrolls rather than overflowing on a small screen.
+      mainContent: Center(
+        child: SingleChildScrollView(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              Center(
+                child: Container(
+                  padding: const EdgeInsets.all(20),
+                  decoration: BoxDecoration(color: colors.semanticEmber.useOpacity(0.12), shape: BoxShape.circle),
+                  child: Icon(Icons.error_outline, size: 72, color: colors.semanticEmber),
+                ),
+              ),
+              const SizedBox(height: 24),
+              Text(
+                title,
+                style: text.titleHero.copyWith(color: colors.semanticEmber),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 16),
+              Text(
+                message,
+                style: text.bodyLarge.copyWith(color: colors.textContent),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 20),
+              Container(
+                padding: const EdgeInsets.all(16),
+                decoration: BoxDecoration(
+                  color: colors.semanticEmber.useOpacity(0.08),
+                  borderRadius: context.radiusV3.mdBorder,
+                  border: Border.all(color: colors.semanticEmber),
+                ),
+                child: detail,
+              ),
+              const SizedBox(height: 20),
+              Text(
+                'Nothing was signed.',
+                style: text.bodyEmphasis.copyWith(color: colors.textMuted),
+                textAlign: TextAlign.center,
+              ),
+            ],
+          ),
+        ),
+      ),
+      bottomContent: ScaffoldBaseBottomContent(
+        child: QuantusButton.simple(label: 'Back to home', onTap: () => Navigator.popUntil(context, (r) => r.isFirst)),
+      ),
+    );
+  }
+}

cold-wallet-app/lib/components/ur_qr_panel.dart

@@ -0,0 +1,75 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:quantus_sdk/quantus_sdk.dart';
+import 'package:quantus_cold_wallet/components/qr_tuning_controls.dart';
+import 'package:quantus_cold_wallet/providers/settings_providers.dart';
+import 'package:quantus_cold_wallet/providers/ur_qr_providers.dart';
+
+/// An animated UR QR of [payload] with its frame/FPS/bytes summary and, for
+/// multi-frame payloads, a pause button that opens the tuning sheet. The
+/// frames and the paused flag live in providers, so every screen that shows
+/// a QR behaves the same and keeps no QR state of its own.
+class UrQrPanel extends ConsumerWidget {
+  final UrPayload payload;
+
+  const UrQrPanel({super.key, required this.payload});
+
+  Future<void> _pauseAndTune(BuildContext context, WidgetRef ref) async {
+    final paused = ref.read(qrPausedProvider.notifier);
+    paused.pause();
+    await BottomSheetContainer.show<void>(
+      context,
+      builder: (ctx) => const BottomSheetContainer(title: 'QR display options', child: QrTuningControls()),
+    );
+    paused.resume();
+  }
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final colors = context.colorsV3;
+    final text = context.themeTextV3;
+    final settings = ref.watch(coldSettingsProvider);
+    final parts = ref.watch(urQrFramesProvider(payload));
+    final paused = ref.watch(qrPausedProvider);
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.center,
+      children: [
+        Center(
+          child: AnimatedUrQr(parts: parts, fps: settings.qrFps, paused: paused),
+        ),
+        const SizedBox(height: 12),
+        Row(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            Text(
+              '${parts.length} ${parts.length == 1 ? 'frame' : 'frames'} · ${settings.qrFps} FPS · '
+              '${settings.qrBytes} bytes',
+              style: text.caption.copyWith(color: colors.textMuted),
+            ),
+            if (parts.length > 1) ...[
+              const SizedBox(width: 12),
+              GestureDetector(
+                onTap: () => _pauseAndTune(context, ref),
+                child: Container(
+                  width: 32,
+                  height: 32,
+                  decoration: BoxDecoration(color: colors.bgSurface2, shape: BoxShape.circle),
+                  child: Icon(Icons.pause_rounded, size: 20, color: colors.textContent),
+                ),
+              ),
+            ],
+          ],
+        ),
+        if (parts.length > 1) ...[
+          const SizedBox(height: 16),
+          Text(
+            'Animated QR — keep both devices steady until the other device finishes scanning.',
+            style: text.caption.copyWith(color: colors.textMuted),
+            textAlign: TextAlign.center,
+          ),
+        ],
+      ],
+    );
+  }
+}

cold-wallet-app/lib/debug/debug_calls_screen.dart

@@ -1,8 +1,12 @@
+import 'dart:typed_data';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:quantus_sdk/quantus_sdk.dart';
+import 'package:quantus_cold_wallet/debug/debug_near_payloads.dart';
 import 'package:quantus_cold_wallet/debug/debug_payloads.dart';
 import 'package:quantus_cold_wallet/providers/wallet_providers.dart';
+import 'package:quantus_cold_wallet/screens/sign_near_transaction_screen.dart';
 import 'package:quantus_cold_wallet/screens/sign_transaction_screen.dart';
 
 /// Every call the signer can be asked to review, one tap from its review
@@ -18,6 +22,7 @@ class DebugCallsScreen extends ConsumerWidget {
     final colors = context.colorsV3;
     final text = context.themeTextV3;
     final signer = ref.watch(addressProvider);
+    final nearSamples = DebugNearPayloads.samples(_nearSigningKey(ref));
 
     return ScaffoldBase(
       appBar: const V2AppBar(title: 'Debug calls'),
@@ -39,33 +44,57 @@ class DebugCallsScreen extends ConsumerWidget {
                 for (final call in DebugPayloads.refused) _row(context, call, signer),
                 _header(context, 'INVALID QR CODE DATA · ${DebugPayloads.invalidQrData.length}', colors.semanticEmber),
                 for (final call in DebugPayloads.invalidQrData) _row(context, call, signer),
+                _header(context, 'NEAR · ${nearSamples.length}', colors.accentFlare),
+                for (final call in nearSamples) _nearRow(context, call),
                 const SizedBox(height: 24),
               ],
             ),
     );
   }
 
+  /// The raw public key of the wallet's first ML-DSA-65 account, the only kind
+  /// of key a NEAR transaction can name here. Null when there is none.
+  Uint8List? _nearSigningKey(WidgetRef ref) {
+    final address = ref
+        .watch(addressesProvider)
+        .entries
+        .where((e) => e.value.scheme == DilithiumScheme.mlDsa65)
+        .firstOrNull
+        ?.key;
+    return address == null ? null : keypairFor(ref, address)?.publicKey;
+  }
+
   Widget _header(BuildContext context, String title, Color color) {
     return Padding(
       padding: const EdgeInsets.only(top: 20, bottom: 8),
       child: Text(title, style: context.themeTextV3.labelMonogram.copyWith(color: color, letterSpacing: 1.2)),
     );
   }
 
-  Widget _row(BuildContext context, DebugCall call, String signer) {
+  Widget _row(BuildContext context, DebugCall call, String signer) => _tile(
+    context,
+    call.label,
+    () => SignTransactionScreen(
+      request: SigningRequest(signer: call.signer ?? signer, payload: DebugPayloads.payloadForCall(call.call)),
+    ),
+  );
+
+  Widget _nearRow(BuildContext context, DebugNearCall call) => _tile(
+    context,
+    call.label,
+    () => SignNearTransactionScreen(
+      request: call.request,
+      transaction: decodeNearTransaction(transaction: call.request.transaction),
+    ),
+  );
+
+  Widget _tile(BuildContext context, String label, Widget Function() screen) {
     final colors = context.colorsV3;
     final text = context.themeTextV3;
 
     return GestureDetector(
       behavior: HitTestBehavior.opaque,
-      onTap: () => Navigator.push(
-        context,
-        MaterialPageRoute(
-          builder: (_) => SignTransactionScreen(
-            request: SigningRequest(signer: call.signer ?? signer, payload: DebugPayloads.payloadForCall(call.call)),
-          ),
-        ),
-      ),
+      onTap: () => Navigator.push(context, MaterialPageRoute(builder: (_) => screen())),
       child: Container(
         padding: const EdgeInsets.symmetric(vertical: 14),
         decoration: BoxDecoration(
@@ -74,7 +103,7 @@ class DebugCallsScreen extends ConsumerWidget {
         child: Row(
           children: [
             Expanded(
-              child: Text(call.label, style: text.body.copyWith(color: colors.textContent)),
+              child: Text(label, style: text.body.copyWith(color: colors.textContent)),
             ),
             Icon(Icons.chevron_right, size: 18, color: colors.textMuted),
           ],