This commit addresses several critical issues across the mobile monorepo:
1. Centralized Error Handling: Integrated DataErrorHandler mixin into all repository implementations, ensuring consistent mapping of Data Connect exceptions to domain AppExceptions.
2. Build Stabilization: Fixed numerous type mismatches, parameter signature errors in widgets (e.g., google_places_flutter itemBuilder), and naming conflicts (StaffSession, FirebaseAuth).
3. Code Quality: Applied 'dart fix' across all modified packages and manually cleared debug print statements and UI clutter.
4. Mono-repo alignment: Standardized Data Connect usage and aliasing ('dc.') for better maintainability.
Signed-off-by: Suriya <suriya@tenext.in>
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.
