feat: support uniqueness validation with optional excludeId for all unique...
feat: support uniqueness validation with optional excludeId for all unique fields of Establishment, Contract, Sector, Agency, Department, and Lot.
- Implemented uniqueness checks for key fields (e.g., name, code, number) across all related entities.
- Added support for an optional ID exclusion parameter to allow updates without false positive conflicts.
- Updated repository, service, and controller layers for: Establishment, Contract, Sector, Agency, Department, and Lot.