feat: Add settings to control play button visibility on home shelves

This commit introduces new functionality to customize the visibility of the
play button on home page shelves.

Key changes:

- Added `HomePageSettings` to `AppSettings` to store your preferences:
    - `showPlayButtonOnContinueShelves`: Controls visibility on "Continue Listening" and "Continue Series" shelves (default: true).
    - `showPlayButtonOnAllShelves`: Controls visibility on other shelves (default: false).
- Modified `BookHomeShelf` to respect these settings when rendering books.
- Created a new "Home Page Settings" page under "Appearance" in App Settings, allowing you to toggle these two options.
- Added comprehensive unit and widget tests to cover the new settings model, the conditional logic in `BookHomeShelf`, and the functionality of the new settings page.

lib/router/router.dart

@@ -18,6 +18,7 @@ import 'package:vaani/settings/view/notification_settings_page.dart';
 import 'package:vaani/settings/view/player_settings_page.dart';
 import 'package:vaani/settings/view/shake_detector_settings_page.dart';
 import 'package:vaani/settings/view/theme_settings_page.dart';
+import 'package:vaani/settings/view/home_page_settings_page.dart';
 
 import 'scaffold_with_nav_bar.dart';
 import 'transitions/slide.dart';
@@ -213,6 +214,13 @@ class MyAppRouter {
                           const ShakeDetectorSettingsPage(),
                         ),
                       ),
+                      GoRoute(
+                        path: Routes.homePageSettings.pathName,
+                        name: Routes.homePageSettings.name,
+                        pageBuilder: defaultPageBuilder(
+                          const HomePageSettingsPage(),
+                        ),
+                      ),
                     ],
                   ),
                   GoRoute(