refactor(online): migrate to PSR-4 architecture with DI controllers
- Extract IndexController, HistoryController, GuestController, IpController
- Add OnlineAdminMiddleware for guest/ip access control
- Add FiltersBuilder service to deduplicate tab filter logic
- Add PageMeta for paginated title/description
- Add config/services.php DI bootstrap
- Update Installer namespace to Johncms\Modules\Online\Install
- Remove legacy index.php and includes/
- Add OnlineAdminMiddleware for guest/ip access control
- Add FiltersBuilder service to deduplicate tab filter logic
- Add PageMeta for paginated title/description
- Add config/services.php DI bootstrap
- Update Installer namespace to Johncms\Modules\Online\Install
- Remove legacy index.php and includes/