Add reject step functionality to contract approval process

- Implemented rejection handling in ContractApprovalStepsCard with a modal for rejection reasons.
- Updated useContractMutations to include rejectStep mutation.
- Added REJECT_STEP URL constant for API integration.
- Enhanced ContractClearanceDetailPage to utilize linkedBookingId for improved booking handling.

apps/edr-freight-web/backoffice/src/services/contracts.service.ts

@@ -185,6 +185,16 @@ export const contractsService = {
       requiredRole,
     }),
 
+  rejectStep: ({
+    id,
+    stepId,
+    reason,
+  }: {
+    id: string;
+    stepId: string;
+    reason: string;
+  }) => postContract<Freight.IContract>(C.REJECT_STEP(id, stepId), { reason }),
+
   // ── Contract document ──
   generateContract: (id: string) =>
     postContract<Freight.IContract>(C.CONTRACT_GENERATE(id)),