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/modules/contracts/entities/contract-signature.entity.ts

@@ -29,6 +29,14 @@ export class ContractSignature extends BaseEntity {
   @JoinColumn({ name: 'signature_file_id' })
   signatureFile?: FileRecord | null;
 
+  /** Company stamp/seal image, uploaded alongside the drawn signature. */
+  @Column({ name: 'stamp_file_id', type: 'uuid', nullable: true })
+  stampFileId?: string | null;
+
+  @ManyToOne(() => FileRecord, { nullable: true })
+  @JoinColumn({ name: 'stamp_file_id' })
+  stampFile?: FileRecord | null;
+
   @Column({ name: 'consent_text', type: 'text', nullable: true })
   consentText?: string | null;