Integrates Objectbox database initialization into the main application startup process.
Adds `path` and `path_provider` as direct dependencies, which are typically required for Objectbox to locate the database directory.
Adds the ObjectBox database dependency for local data persistence.
Updates the Product ID field type from nullable String to non-nullable int with a default value of 0 to align with ObjectBox's integer ID requirements. Includes necessary generated files for plugin registration and model serialization.
Replaces hardcoded colors and standard Theme.of(context) accesses with a custom AppTheme.
Introduces distinct light and dark themes and persists the selected theme mode using shared_preferences.
Integrates the theme into the main app structure and applies it to various components and pages.
Adds google_fonts dependency for theme typography.
