feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

mobile/test/shared/widgets/avatar_image_test.dart

@@ -0,0 +1,74 @@
+import 'dart:convert';
+
+import 'package:buzz/shared/widgets/avatar_image.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_svg/flutter_svg.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  const svg =
+      '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32">'
+      '<text x="16" y="24" text-anchor="middle">🦝</text></svg>';
+
+  Widget subject(String? imageUrl) => MaterialApp(
+    home: AvatarImage(
+      imageUrl: imageUrl,
+      radius: 16,
+      fallback: const Text('R'),
+    ),
+  );
+
+  testWidgets('renders raccoon percent-encoded SVG data avatar', (
+    tester,
+  ) async {
+    const raccoonAvatar =
+        'data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22512%22%20height%3D%22512%22%20viewBox%3D%220%200%20512%20512%22%3E%3Crect%20width%3D%22512%22%20height%3D%22512%22%20rx%3D%22256%22%20fill%3D%22%233399FF%22%2F%3E%3Ctext%20x%3D%2250%25%22%20y%3D%2256%25%22%20dominant-baseline%3D%22middle%22%20text-anchor%3D%22middle%22%20font-size%3D%22258%22%3E%F0%9F%A6%9D%3C%2Ftext%3E%3C%2Fsvg%3E';
+    await tester.pumpWidget(subject(raccoonAvatar));
+    await tester.pumpAndSettle();
+
+    final emoji = tester.widget<Text>(find.text('🦝'));
+    expect(emoji.style?.height, 1);
+    expect(find.byType(SvgPicture), findsNothing);
+    expect(find.text('R'), findsNothing);
+    expect(tester.takeException(), isNull);
+  });
+
+  testWidgets('renders base64 SVG data avatar', (tester) async {
+    await tester.pumpWidget(
+      subject('data:image/svg+xml;base64,${base64Encode(utf8.encode(svg))}'),
+    );
+
+    expect(find.byType(SvgPicture), findsOneWidget);
+  });
+
+  testWidgets('centers fallback when no avatar is configured', (tester) async {
+    await tester.pumpWidget(subject(null));
+
+    final avatarCenter = tester.getCenter(find.byType(CircleAvatar));
+    final fallbackCenter = tester.getCenter(find.text('R'));
+    expect(fallbackCenter, avatarCenter);
+  });
+
+  testWidgets('uses fallback for malformed image data', (tester) async {
+    await tester.pumpWidget(subject('data:image/svg+xml;base64,%%%'));
+
+    expect(find.text('R'), findsOneWidget);
+  });
+
+  testWidgets('reuses parsed raster bytes across parent rebuilds', (
+    tester,
+  ) async {
+    const png =
+        'data:image/png;base64,'
+        'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=';
+    await tester.pumpWidget(subject(png));
+    final firstBytes = tester.widget<Image>(find.byType(Image)).image;
+
+    await tester.pumpWidget(subject(png));
+    final rebuiltBytes = tester.widget<Image>(find.byType(Image)).image;
+
+    final firstMemory = firstBytes as MemoryImage;
+    final rebuiltMemory = rebuiltBytes as MemoryImage;
+    expect(rebuiltMemory.bytes, same(firstMemory.bytes));
+  });
+}