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/contract-pricing.service.ts

@@ -35,6 +35,8 @@ function toContractUnit(rateUnit: string): ContractUnitRateLineItem['unit'] {
   switch (rateUnit) {
     case 'PER_TON':
       return 'per_ton';
+    case 'PER_ITEM':
+      return 'per_item';
     case 'PER_KM':
       return 'per_km';
     case 'PER_WAGON':
@@ -115,9 +117,19 @@ export class ContractPricingService {
         });
       }
     } else {
-      const bulkRate =
-        liveRates.find((r) => r.rateType === baseType && r.currency === 'USD') ?? null;
       const cargoScope = (contract.cargoScope ?? []).find((c) => c.cargoTypeId);
+      // Freeze the rate for the contract's own commodity when one is configured
+      // — a per-item machinery rate and a per-ton wheat rate live side by side.
+      const bulkRates = liveRates.filter(
+        (r) => r.rateType === baseType && r.currency === 'USD',
+      );
+      const bulkRate =
+        (cargoScope?.cargoTypeId
+          ? bulkRates.find((r) => r.cargoTypeId === cargoScope.cargoTypeId)
+          : undefined) ??
+        bulkRates.find((r) => !r.cargoTypeId) ??
+        bulkRates[0] ??
+        null;
       if (bulkRate) {
         lineItems.push({
           code: 'BULK_FREIGHT',