Refactor tender detail models and UI components for improved clarity and functionality

- Updated the `Lot`, `Organization`, and `OrganizationAddress` models to enhance data mapping for tender details.
- Revised the `TenderData` model to include additional fields reflecting the API response structure.
- Improved UI components across desktop, mobile, and tablet views by commenting out unused sections for future use.
- Added new string constants for lot details in the tender information section.
- Enhanced unit tests to cover new model fields and ensure resilience to partial API payloads.

lib/views/shared/desktop_navigation_widget.dart

@@ -87,30 +87,9 @@ class DesktopNavigationWidget extends StatelessWidget {
             iconPath: AssetsManager.tenders,
             activeIconPath: AssetsManager.tendersActive,
           ),
-          // AI-NOTE (for PR reviewer): Board tab disabled (commented, not
-          // removed) to hide the Board page from desktop navigation per request.
-          // The Board route/page itself is left intact; re-enable this nav item
-          // to bring the tab back. Note the tab indices of later items are
-          // unchanged because this block is fully commented out.
-          // const SizedBox(width: 24),
-          // _navigationItem(
-          //   context: context,
-          //   text: TendersStrings.board,
-          //   isActive: currentIndex == 2,
-          //   onTap: () {
-          //     if (currentIndex == 2) {
-          //       return;
-          //     } else {
-          //       Router.neglect(
-          //         context,
-          //         () => const BoardRouteData().go(context),
-          //       );
-          //       //    context.read<TendersViewModel>().getTenders();
-          //     }
-          //   },
-          //   iconPath: AssetsManager.board,
-          //   activeIconPath: AssetsManager.boardActive,
-          // ),
+          // Board tab is intentionally hidden from desktop navigation. The
+          // Board route/page itself remains intact; the nav item (at tab index
+          // 2) can be restored from git history when the feature is re-enabled.
           const SizedBox(width: 24),
           _navigationItem(
             context: context,