Implement contract document download functionality and enhance clearance review status checks

- Added methods to assert clearance reviewable, finalizable, and uploadable statuses in the ContractClearanceService.
- Introduced a new endpoint in ContractsController for downloading contract PDFs.
- Implemented download functionality in the contracts service for both backoffice and portal applications.
- Updated UI components to include download buttons for contract PDFs in relevant pages.
- Enhanced contract request and view pages to support contract document downloads.

apps/edr-freight-api/src/modules/contracts/contract-transition.service.ts

@@ -345,6 +345,14 @@ export class ContractTransitionService {
     return { view, html, signatures: view.signatures };
   }
 
+  /** Lazy-generate (or refresh) the stored contract PDF and stream it for download. */
+  async streamContractPdf(contractId: string) {
+    const contract = await this.contractsService.findById(contractId);
+    const { view } = await this.documentViewModelBuilder.build(contractId);
+    const record = await this.upsertContractPdf(contractId, contract.reference, view);
+    return this.filesService.streamById(record.id);
+  }
+
   /**
    * Rebuild the stored `contract` PDF from the current aggregate (now including
    * the latest signatures) so the downloaded/viewed file matches the live HTML