refactor: remove Slide.error from core

packages/core/lib/src/models/slide_model.dart

@@ -72,35 +72,6 @@ class Slide with SlideMappable {
 
   /// Validates [map] against the schema and constructs a [Slide].
   static Slide parse(Map<String, Object?> map) => fromMap(schema.parse(map)!);
-
-  /// Creates an error slide to display errors in the presentation.
-  ///
-  /// This slide is automatically generated when there are parsing errors
-  /// or other issues loading the presentation.
-  static Slide error({
-    required String title,
-    required String message,
-    required Exception error,
-  }) {
-    return Slide(
-      key: 'error',
-      sections: [
-        SectionBlock([
-          ContentBlock('''
-> [!CAUTION]
-> $title
-> $message
-
-
-```dart
-${error.toString()}
-```
-'''),
-          ContentBlock(''),
-        ]),
-      ],
-    );
-  }
 }
 
 /// Configuration options for a slide.

packages/core/test/src/models/slide_model_test.dart

@@ -266,53 +266,6 @@ void main() {
         });
       });
 
-      group('error factory', () {
-        test('creates error slide with correct key', () {
-          final slide = Slide.error(
-            title: 'Error Title',
-            message: 'Error message',
-            error: Exception('Test error'),
-          );
-
-          expect(slide.key, 'error');
-        });
-
-        test('includes title and message in content', () {
-          final slide = Slide.error(
-            title: 'Parse Error',
-            message: 'Could not parse slide',
-            error: Exception('Details'),
-          );
-
-          final content = (slide.sections[0].blocks[0] as ContentBlock).content;
-          expect(content.contains('Parse Error'), isTrue);
-          expect(content.contains('Could not parse slide'), isTrue);
-        });
-
-        test('includes error details in code block', () {
-          final slide = Slide.error(
-            title: 'Error',
-            message: 'Message',
-            error: Exception('Detailed error info'),
-          );
-
-          final content = (slide.sections[0].blocks[0] as ContentBlock).content;
-          expect(content.contains('Detailed error info'), isTrue);
-          expect(content.contains('```dart'), isTrue);
-        });
-
-        test('creates section with two content blocks', () {
-          final slide = Slide.error(
-            title: 'E',
-            message: 'M',
-            error: Exception('X'),
-          );
-
-          expect(slide.sections.length, 1);
-          expect(slide.sections[0].blocks.length, 2);
-        });
-      });
-
       group('equality', () {
         test('equal slides are equal', () {
           final slide1 = Slide(key: 'same', comments: ['note']);