build: add reproducible Android release verification

Pin Gradle inputs and dependency metadata, then enforce analyze, lint, build, R8, immutability, and regression gates in CI.

test/runtime_boundary_regression_test.dart

@@ -0,0 +1,58 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('notification updates do not trust ActivityManager process visibility', () {
+    final source = File(
+      'android/app/src/main/kotlin/com/paladinvpn/app/MainActivity.kt',
+    ).readAsStringSync();
+
+    expect(source, isNot(contains('ActivityManager')));
+    expect(source, isNot(contains('isVpnServiceProcessAlive')));
+    expect(source, isNot(contains('VPN_PROCESS_SUFFIX')));
+    expect(source, contains('NotificationManagerCompat.from(this).notify'));
+  });
+
+  test('SOCKS reads use one total deadline instead of per-chunk timeout', () {
+    final source = File('lib/logic/local_socks_tester.dart').readAsStringSync();
+
+    expect(
+      source,
+      contains('timeout.inMicroseconds - elapsed.elapsedMicroseconds'),
+    );
+    expect(
+      source,
+      contains("throw TimeoutException('Socket read timed out', timeout);"),
+    );
+  });
+
+  test('Hivemind captures cancellation generation before first async lookup', () {
+    final source = File('lib/logic/hivemind_service.dart').readAsStringSync();
+    final callIdIndex = source.indexOf('final callId = ++_currentCallId;');
+    final deviceIdIndex =
+        source.indexOf('final deviceId = await CryptoService.getDeviceId();');
+
+    expect(callIdIndex, greaterThanOrEqualTo(0));
+    expect(deviceIdIndex, greaterThan(callIdIndex));
+    expect(
+      source.substring(deviceIdIndex),
+      contains('_throwIfCancelled(callId);'),
+    );
+    expect(
+      source,
+      contains('_currentCallId++;\n    _expectedNonce = null;'),
+    );
+  });
+
+  test('notification text is cached only after native update succeeds', () {
+    final source =
+        File('lib/logic/notification_service.dart').readAsStringSync();
+    final invokeIndex =
+        source.indexOf("await _channel.invokeMethod<void>('updateNotificationText'");
+    final cacheIndex = source.indexOf('_lastText = text;');
+
+    expect(invokeIndex, greaterThanOrEqualTo(0));
+    expect(cacheIndex, greaterThan(invokeIndex));
+  });
+}