fix: handle description and bio as String or Map in Work/Author models

[ketanchoyal]

Problem

The OpenLibrary API returns certain text fields in two different formats, but the package models only handle the simple string format.

Affected Fields

1. Work.description - Returns either:

   { "description": "Simple text" }

   or:

   { "description": { "type": "/type/text", "value": "Structured text" } }

2. Author.bio - Returns either:

   { "bio": "Simple bio text" }

   or:

   { "bio": { "type": "/type/text", "value": "Structured bio text" } }

Error

When the API returns the object format, the current code throws:

type '_Map<String, dynamic>' is not a subtype of type 'String?' in type cast

This caused:

• Work fetches to fail completely
• Author fetches to fail silently (resulting in empty author names in library)

Solution

Added custom JSON converters for both fields:

/// Handles both String and Map formats from OpenLibrary API
String? _descriptionFromJson(dynamic value) {
  if (value == null) return null;
  if (value is String) return value;
  if (value is Map) return value['value'] as String?;
  return null;
}

Applied via @JsonKey(fromJson: _descriptionFromJson) annotation.

Testing

• ✅ Code compiles without errors
• ✅ flutter analyze passes
• ✅ Tested with real OpenLibrary API responses

Example API Responses

• Work with structured description: https://openlibrary.org/works/OL82536W.json
• Author with structured bio: https://openlibrary.org/authors/OL26320A.json

Impact

• Breaking Change: No
• Backward Compatible: Yes
• Files Changed: work_edition.dart, author.dart + generated files