refactor: create separate BLoCs for each screen with comprehensive tests

- Created 8 separate BLoCs (Home, Library, BookDetails, AddBook, Scanner, Categories, Wishlist, Settings)
- Each BLoC has its own event, state, and bloc files
- Added 70 comprehensive tests covering all BLoC functionality
- All tests passing (70/70)
- Fixed linting issues and updated deprecated APIs
- Improved code organization and maintainability

bookshelf_flutter/lib/models/models.dart

@@ -0,0 +1,185 @@
+import 'package:flutter/material.dart';
+
+// App screen enum
+enum AppScreen {
+  library,
+  categories,
+  wishlist,
+  settings,
+  details,
+  addBook,
+  scanner,
+}
+
+// Book status enum
+enum BookStatus {
+  reading,
+  done,
+  wantToRead,
+}
+
+// Extension for BookStatus to get display name
+extension BookStatusExtension on BookStatus {
+  String get displayName {
+    switch (this) {
+      case BookStatus.reading:
+        return 'Reading Now';
+      case BookStatus.done:
+        return 'Completed';
+      case BookStatus.wantToRead:
+        return 'Wishlist';
+    }
+  }
+}
+
+// Category record - using Dart records as data classes
+typedef Category = ({
+  String id,
+  String name,
+  int count,
+  IconData icon,
+  String colorClass,
+});
+
+// Book record - using Dart records as data classes
+typedef Book = ({
+  String id,
+  String title,
+  String author,
+  String genre,
+  String annotation,
+  String? coverUrl,
+  int? pages,
+  String? language,
+  int? publishedYear,
+  double? rating,
+  BookStatus status,
+  int? progress,
+  bool isFavorite,
+});
+
+// Helper function to create a Category record
+Category createCategory({
+  required String id,
+  required String name,
+  required int count,
+  required IconData icon,
+  required String colorClass,
+}) {
+  return (
+    id: id,
+    name: name,
+    count: count,
+    icon: icon,
+    colorClass: colorClass,
+  );
+}
+
+// Helper function to create a Book record
+Book createBook({
+  required String id,
+  required String title,
+  required String author,
+  required String genre,
+  required String annotation,
+  String? coverUrl,
+  int? pages,
+  String? language,
+  int? publishedYear,
+  double? rating,
+  required BookStatus status,
+  int? progress,
+  required bool isFavorite,
+}) {
+  return (
+    id: id,
+    title: title,
+    author: author,
+    genre: genre,
+    annotation: annotation,
+    coverUrl: coverUrl,
+    pages: pages,
+    language: language,
+    publishedYear: publishedYear,
+    rating: rating,
+    status: status,
+    progress: progress,
+    isFavorite: isFavorite,
+  );
+}
+
+// Extension to create Book from partial data
+extension BookExtension on Book {
+  Book copyWith({
+    String? id,
+    String? title,
+    String? author,
+    String? genre,
+    String? annotation,
+    String? coverUrl,
+    int? pages,
+    String? language,
+    int? publishedYear,
+    double? rating,
+    BookStatus? status,
+    int? progress,
+    bool? isFavorite,
+  }) {
+    return createBook(
+      id: id ?? this.id,
+      title: title ?? this.title,
+      author: author ?? this.author,
+      genre: genre ?? this.genre,
+      annotation: annotation ?? this.annotation,
+      coverUrl: coverUrl ?? this.coverUrl,
+      pages: pages ?? this.pages,
+      language: language ?? this.language,
+      publishedYear: publishedYear ?? this.publishedYear,
+      rating: rating ?? this.rating,
+      status: status ?? this.status,
+      progress: progress ?? this.progress,
+      isFavorite: isFavorite ?? this.isFavorite,
+    );
+  }
+
+  // Convert to JSON for storage/transport
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'title': title,
+      'author': author,
+      'genre': genre,
+      'annotation': annotation,
+      'coverUrl': coverUrl,
+      'pages': pages,
+      'language': language,
+      'publishedYear': publishedYear,
+      'rating': rating,
+      'status': status.name,
+      'progress': progress,
+      'isFavorite': isFavorite,
+    };
+  }
+
+  // Create Book from JSON
+  static Book fromJson(Map<String, dynamic> json) {
+    return (
+      id: json['id'] as String,
+      title: json['title'] as String,
+      author: json['author'] as String,
+      genre: json['genre'] as String,
+      annotation: json['annotation'] as String,
+      coverUrl: json['coverUrl'] as String?,
+      pages: json['pages'] as int?,
+      language: json['language'] as String?,
+      publishedYear: json['publishedYear'] as int?,
+      rating: (json['rating'] as num?)?.toDouble(),
+      status: BookStatus.values.firstWhere(
+        (e) => e.name == json['status'],
+        orElse: () => BookStatus.wantToRead,
+      ),
+      progress: json['progress'] as int?,
+      isFavorite: json['isFavorite'] as bool? ?? false,
+    );
+  }
+}