fix(#284): summarise GIF notifications via GifHelper, not a duplicate regex

Notifications summarised a GIF as "Sent a GIF" using their own hand-rolled
`^g:[A-Za-z0-9_-]+$` regex rather than GifHelper. #282 changed the payload to
`https://giphy.com/gifs/<id>`, which that regex does not match, so GIF
notifications regressed to dumping the raw URL into the tray.

Detection now goes through `GifHelper.parseGif`, matching how the adjacent
reaction case already delegates to ReactionHelper. That restores the summary
and covers every form the app can send, including replies (`@[Name] ` +
payload), which the old regex never matched even for legacy `g:<id>`.

Verified no other hand-rolled `^g:`/`^m:`/`^s:`/`^r:` payload regexes remain
outside their owning helpers, so this class of drift is closed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/services/notification_service.dart

@@ -4,6 +4,7 @@ import 'dart:ui';
 import 'package:flutter_local_notifications/flutter_local_notifications.dart';
 import 'package:flutter/foundation.dart';
 
+import '../helpers/gif_helper.dart';
 import '../helpers/reaction_helper.dart';
 import '../l10n/app_localizations.dart';
 import '../utils/platform_info.dart';
@@ -154,7 +155,7 @@ class NotificationService {
     if (reaction != null) {
       return 'Reacted ${reaction.emoji}';
     }
-    if (RegExp(r'^g:[A-Za-z0-9_-]+$').hasMatch(trimmed)) {
+    if (GifHelper.parseGif(trimmed) != null) {
       return 'Sent a GIF';
     }
     return text;

test/services/notification_text_test.dart

@@ -0,0 +1,67 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_open/helpers/gif_helper.dart';
+import 'package:meshcore_open/services/notification_service.dart';
+
+// #284: notifications summarised a GIF as "Sent a GIF" using their own
+// hand-rolled `^g:<id>$` regex. #282 changed the payload to a Giphy URL, which
+// that regex does not match, so notifications regressed to dumping the raw URL.
+// Detection must go through GifHelper.parseGif so every payload form the app
+// can actually send is summarised, and so the regex cannot drift again.
+void main() {
+  const gifId = 'zaMiq1BvCdAVIiu3Mb';
+
+  group('GIF payloads are summarised, not dumped raw', () {
+    test('the current URL payload summarises', () {
+      expect(
+        NotificationService.formatNotificationText(GifHelper.encodeGif(gifId)),
+        'Sent a GIF',
+      );
+    });
+
+    test('a reply carrying a GIF summarises', () {
+      expect(
+        NotificationService.formatNotificationText(
+          '@[Some Node] ${GifHelper.encodeGif(gifId)}',
+        ),
+        'Sent a GIF',
+      );
+    });
+
+    test('a legacy g:<id> payload still summarises', () {
+      expect(
+        NotificationService.formatNotificationText('g:$gifId'),
+        'Sent a GIF',
+      );
+    });
+
+    test('a legacy g:<id> reply still summarises', () {
+      expect(
+        NotificationService.formatNotificationText('@[Some Node] g:$gifId'),
+        'Sent a GIF',
+      );
+    });
+  });
+
+  group('everything else is untouched', () {
+    test('a reaction still summarises', () {
+      expect(
+        NotificationService.formatNotificationText('r:abcd:00'),
+        startsWith('Reacted '),
+      );
+    });
+
+    test('ordinary text passes through unchanged', () {
+      expect(
+        NotificationService.formatNotificationText('hey are you there'),
+        'hey are you there',
+      );
+    });
+
+    test('a non-GIF URL is not mistaken for a GIF', () {
+      expect(
+        NotificationService.formatNotificationText('https://example.com/page'),
+        'https://example.com/page',
+      );
+    });
+  });
+}