feat: record reason for automatic rejection

Author: fricklerhandwerk

src/shared/listeners/automatic_linkage.py

@@ -113,6 +113,7 @@ def build_new_links(container: Container) -> bool:
         CVEDerivationClusterProposal.objects.create(
             cve=container.cve,
             status=CVEDerivationClusterProposal.Status.REJECTED,
+            rejection_reason=CVEDerivationClusterProposal.RejectionReason.EXCLUSIVELY_HOSTED_SERVICE,
         )
         return True
 

src/shared/tests/test_linkage.py

@@ -138,4 +138,8 @@ def test_exclusively_hosted_service_creates_rejected_proposal(
     assert result is True
     proposal = CVEDerivationClusterProposal.objects.get(cve=container.cve)
     assert proposal.status == CVEDerivationClusterProposal.Status.REJECTED
+    assert (
+        proposal.rejection_reason
+        == CVEDerivationClusterProposal.RejectionReason.EXCLUSIVELY_HOSTED_SERVICE
+    )
     assert proposal.derivations.count() == 0