증분백업 로직 개선

.gitea/workflows/mirror.yml

@@ -226,6 +226,10 @@ jobs:
               fi
               git remote add origin "${GITEA_REMOTE}"
               git remote add source "${source_repo_url}"
+              echo "Seeding objects from target main for delta fetch..."
+              if ! git fetch --no-tags origin "+refs/heads/main:refs/heads/main"; then
+                echo "::warning::Failed to fetch target main; continuing without seed"
+              fi
             fi
 
             echo "Fetching latest branch '${branch_name}' from source..."