add company stamp upload functionality for contract signing

- Introduced StampUpload component for uploading company stamp images.
- Integrated stamp upload in contract signing modal, supporting PNG and JPG formats.
- Implemented validation for file type and size (max 5 MB).
- Added visual feedback for drag-and-drop functionality.
- Updated contract-related pages to handle duplicate contract alerts and pricing notices.
- Enhanced contract expiry management with a nightly sweep service.
- Added unit tests for new features and updated existing tests for contract handling.

apps/edr-freight-api/src/contracts/contract-document-view-model.builder.ts

@@ -30,6 +30,8 @@ export interface ContractDocumentSignatureView {
   signerDisplayName: string;
   signedAt: string;
   signatureImageUrl?: string | null;
+  /** Company stamp/seal; rendered next to the signature when present. */
+  stampImageUrl?: string | null;
 }
 
 /** A single unit-rate row on the contract PDF — price per unit, NO total. */
@@ -208,6 +210,7 @@ export class ContractDocumentViewModelBuilder {
       signerDisplayName: row.signerDisplayName,
       signedAt: this.formatDate(row.signedAt),
       signatureImageUrl: row.signatureFile?.url ?? null,
+      stampImageUrl: row.stampFile?.url ?? null,
     };
   }