- Add transactional product registration and modification with COA assignment
- Store invoice-item unit prices and require a chart-of-accounts relation
- Remove defaults from client credentials and chart-of-account status
- Remove legacy invoicing actions and DTOs
- Introduced `ChartOfAccount` model with parent-child relationships, casting, and policy integration.
- Defined DTOs and actions for registering, adjusting, and suspending accounts (`RegisterChartOfAccount`, `AdjustAccountClassification`, `SuspendAccountPostings`).
- Added enums for account classifications and balances.
- Created `AccountingServiceProvider` and `RelationshipServiceProvider` for domain initialization and runtime relationship binding.
- Migrated COA-related logic from Billing domain and removed redundant files.
- Updated DataTables, Livewire forms, and localization for COA and product management.