Introduces the first versions of client and staff mobile application prototypes, including platform-specific assets, screens, and configuration for Android, iOS, macOS, Linux, and Windows. Adds documentation, AI prompt guides, and a new staff payments feature module with repository, use cases, and presentation logic. Also includes generated localization files and supporting resources for both client and staff apps.
Relocated all app directories (client, design_system_viewer, staff) and their contents under the new 'apps/mobile' path. This change improves project organization and prepares for future platform-specific structuring.
