fix failure to decode repo metadata from package records

Author: tayloraswift

Sources/UnidocDB/Packages/PackageDatabase.Packages.Placement.swift

@@ -13,6 +13,7 @@ extension PackageDatabase.Packages
         init(coordinate:Int32, repo:PackageRepo?, new:Bool)
         {
             self.coordinate = coordinate
+            self.repo = repo
             self.new = new
         }
     }

Sources/UnidocServer/Endpoints/Server.Endpoint._SyncRepository.swift

@@ -56,6 +56,8 @@ extension Server.Endpoint._SyncRepository:RestrictedOperation
 
         return .resource(.init(.one(canonical: nil),
             content: .string("""
+                Cell: \(package)
+
                 \(repo)
 
                 Known Tags: \(old)