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/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -0,0 +1,16 @@
+//
+//  Generated file. Do not edit.
+//
+
+import FlutterMacOS
+import Foundation
+
+import file_selector_macos
+import path_provider_foundation
+import sqflite_darwin
+
+func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  FileSelectorPlugin.register(with: registry.registrar(forPlugin: "FileSelectorPlugin"))
+  PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
+  SqflitePlugin.register(with: registry.registrar(forPlugin: "SqflitePlugin"))
+}