appview: handle deleted forks

appview/pages/templates/repo/pulls/pulls.html

···
                     </span>
                     {{ if not .IsPatchBased }}
                     <span>from
-                      {{ if not .IsBranchBased }}
+                      {{ if .IsForkBased }}
+                        {{ if .PullSource.Repo }}
                         <a href="/{{ $owner }}/{{ .PullSource.Repo.Name }}" class="no-underline hover:underline">{{ $owner }}/{{ .PullSource.Repo.Name }}</a>
+                        {{ else }}
+                        <span class="italic">[deleted fork]</span>
+                        {{ end }}
                       {{ end }}
 
                       <span class="text-xs rounded bg-gray-100 dark:bg-gray-700 text-black dark:text-white font-mono px-2 mx-1/2 inline-flex items-center">

appview/state/pull.go

···
 				pullSourceRepo, err = db.GetRepoByAtUri(s.db, p.PullSource.RepoAt.String())
 				if err != nil {
 					log.Printf("failed to get repo by at uri: %v", err)
-					return
+					continue
+				} else {
+					p.PullSource.Repo = pullSourceRepo
 				}
 			}
-			p.PullSource.Repo = pullSourceRepo
 		}
 	}