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-web/backoffice/src/components/bookings/detail/ClearanceReviewSection.tsx

@@ -419,6 +419,7 @@ function DocReviewCard({
   const status = doc.reviewStatus ?? "PENDING";
   const meta = STATUS_META[status];
   const hasFile = !!doc.file;
+  const isApproved = status === "APPROVED";
 
   return (
     <Paper
@@ -514,16 +515,18 @@ function DocReviewCard({
               >
                 Open query
               </Button>
-              <Button
-                size="compact-sm"
-                color="edr-green"
-                radius="md"
-                leftSection={<CheckCircle2 size={14} />}
-                disabled={busy}
-                onClick={onApprove}
-              >
-                Approve
-              </Button>
+              {!isApproved && (
+                <Button
+                  size="compact-sm"
+                  color="edr-green"
+                  radius="md"
+                  leftSection={<CheckCircle2 size={14} />}
+                  disabled={busy}
+                  onClick={onApprove}
+                >
+                  Approve
+                </Button>
+              )}
             </Group>
           ) : (
             <Box