test: aggiungi unit test per UpdateService

Copre parseVersion (semver standard, parti mancanti, valori non numerici)
e isNewer (patch/minor/major bump, versione uguale, versione più vecchia,
componenti multi-cifra come 2.0.10 > 2.0.9). 10/10 test passati su ARM64.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

test/shared/services/update_service_test.dart

@@ -0,0 +1,51 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:biteplan/shared/services/update_service.dart';
+
+void main() {
+  group('UpdateService.parseVersion', () {
+    test('parses standard semver', () {
+      expect(UpdateService.parseVersion('2.1.3'), [2, 1, 3]);
+    });
+
+    test('pads missing parts with zeros', () {
+      expect(UpdateService.parseVersion('2.1'), [2, 1, 0]);
+      expect(UpdateService.parseVersion('2'), [2, 0, 0]);
+    });
+
+    test('handles non-numeric parts as zero', () {
+      expect(UpdateService.parseVersion('2.x.3'), [2, 0, 3]);
+    });
+  });
+
+  group('UpdateService.isNewer', () {
+    test('patch bump is newer', () {
+      expect(UpdateService.isNewer('2.0.1', '2.0.0'), isTrue);
+    });
+
+    test('minor bump is newer', () {
+      expect(UpdateService.isNewer('2.1.0', '2.0.9'), isTrue);
+    });
+
+    test('major bump is newer', () {
+      expect(UpdateService.isNewer('3.0.0', '2.9.9'), isTrue);
+    });
+
+    test('same version is not newer', () {
+      expect(UpdateService.isNewer('2.0.0', '2.0.0'), isFalse);
+    });
+
+    test('older remote is not newer', () {
+      expect(UpdateService.isNewer('1.9.9', '2.0.0'), isFalse);
+    });
+
+    test('remote with v-prefix stripped is handled correctly', () {
+      // tag_name comes in already stripped of 'v' by checkUpdate
+      expect(UpdateService.isNewer('2.0.1', '2.0.0'), isTrue);
+    });
+
+    test('multi-digit version components', () {
+      expect(UpdateService.isNewer('2.0.10', '2.0.9'), isTrue);
+      expect(UpdateService.isNewer('2.10.0', '2.9.0'), isTrue);
+    });
+  });
+}