Moves page files from verbose `*_page` named directories to simpler, more organized paths.
This includes:
- Renaming top-level pages (e.g., `home_page` to `home`, `login_page` to `login`).
- Nesting related pages under common directories (e.g., `product_form_page` and `product_list_page` are now under `product/`).
The update improves project organization, reduces verbosity in file paths, and enhances overall maintainability.
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.
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.
