feat(playback): add ArtCNN shader presets

close #924

test/models/shader_preset_test.dart

@@ -0,0 +1,57 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:plezy/models/shader_preset.dart';
+
+void main() {
+  group('ShaderPreset ArtCNN presets', () {
+    test('exposes stable built-in preset ids in the expected order', () {
+      final ids = ShaderPreset.allPresets.map((preset) => preset.id).toList();
+
+      expect(ids.take(8), [
+        ShaderPreset.none.id,
+        ShaderPreset.nvscalerDefault.id,
+        'artcnn_c4f16_neutral',
+        'artcnn_c4f16_dn',
+        'artcnn_c4f16_ds',
+        'artcnn_c4f32_neutral',
+        'artcnn_c4f32_dn',
+        'artcnn_c4f32_ds',
+      ]);
+    });
+
+    test('creates ArtCNN presets with names, type, and config', () {
+      final neutral = ShaderPreset.artcnnPreset(ArtCNNModel.c4f16, ArtCNNVariant.neutral);
+      final denoise = ShaderPreset.artcnnPreset(ArtCNNModel.c4f32, ArtCNNVariant.denoise);
+      final sharpen = ShaderPreset.artcnnPreset(ArtCNNModel.c4f32, ArtCNNVariant.denoiseSharpen);
+
+      expect(neutral.id, 'artcnn_c4f16_neutral');
+      expect(neutral.name, 'ArtCNN C4F16');
+      expect(neutral.type, ShaderPresetType.artcnn);
+      expect(neutral.artcnnConfig, const ArtCNNConfig(model: ArtCNNModel.c4f16, variant: ArtCNNVariant.neutral));
+      expect(neutral.artcnnModelDisplayName, 'C4F16');
+
+      expect(denoise.id, 'artcnn_c4f32_dn');
+      expect(denoise.name, 'ArtCNN C4F32 Denoise');
+      expect(denoise.artcnnConfig, const ArtCNNConfig(model: ArtCNNModel.c4f32, variant: ArtCNNVariant.denoise));
+
+      expect(sharpen.id, 'artcnn_c4f32_ds');
+      expect(sharpen.name, 'ArtCNN C4F32 Denoise + Sharpen');
+      expect(sharpen.artcnnConfig, const ArtCNNConfig(model: ArtCNNModel.c4f32, variant: ArtCNNVariant.denoiseSharpen));
+    });
+
+    test('finds ArtCNN presets by id', () {
+      final preset = ShaderPreset.fromId('artcnn_c4f32_ds');
+
+      expect(preset, isNotNull);
+      expect(preset!.type, ShaderPresetType.artcnn);
+      expect(preset.artcnnConfig, const ArtCNNConfig(model: ArtCNNModel.c4f32, variant: ArtCNNVariant.denoiseSharpen));
+    });
+
+    test('round-trips ArtCNN config through json', () {
+      final preset = ShaderPreset.artcnnPreset(ArtCNNModel.c4f16, ArtCNNVariant.denoise);
+      final decoded = ShaderPreset.fromJson(preset.toJson());
+
+      expect(decoded, preset);
+      expect(decoded.artcnnConfig, preset.artcnnConfig);
+    });
+  });
+}

test/providers/shader_provider_test.dart

@@ -33,6 +33,12 @@ void main() {
       final ids = p.allPresets.map((preset) => preset.id).toList();
       expect(ids, contains(ShaderPreset.none.id));
       expect(ids, contains(ShaderPreset.nvscalerDefault.id));
+      expect(ids, contains('artcnn_c4f16_neutral'));
+      expect(ids, contains('artcnn_c4f16_dn'));
+      expect(ids, contains('artcnn_c4f16_ds'));
+      expect(ids, contains('artcnn_c4f32_neutral'));
+      expect(ids, contains('artcnn_c4f32_dn'));
+      expect(ids, contains('artcnn_c4f32_ds'));
       expect(p.allPresets.length, ShaderPreset.allPresets.length);
 
       p.dispose();