appview: use typed request helper for RepoIndexResponse

appview/state/repo.go

···
 		return
 	}
 
-	resp, err := us.Index(f.OwnerDid(), f.RepoName, ref)
+	result, err := us.Index(f.OwnerDid(), f.RepoName, ref)
 	if err != nil {
 		s.pages.Error503(w)
 		log.Println("failed to reach knotserver", err)
-		return
-	}
-	defer resp.Body.Close()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		log.Printf("Error reading response body: %v", err)
-		return
-	}
-
-	var result types.RepoIndexResponse
-	err = json.Unmarshal(body, &result)
-	if err != nil {
-		log.Printf("Error unmarshalling response body: %v", err)
 		return
 	}
 
···
 		LoggedInUser:       user,
 		RepoInfo:           repoInfo,
 		TagMap:             tagMap,
-		RepoIndexResponse:  result,
+		RepoIndexResponse:  *result,
 		CommitsTrunc:       commitsTrunc,
 		TagsTrunc:          tagsTrunc,
 		ForkInfo:           forkInfo,

knotclient/signer.go

···
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"io"
+	"log"
 	"net/http"
 	"net/url"
 	"time"

knotclient/unsigned.go

···
 	return &result, nil
 }
 
-func (us *UnsignedClient) Index(ownerDid, repoName, ref string) (*http.Response, error) {
+func (us *UnsignedClient) Index(ownerDid, repoName, ref string) (*types.RepoIndexResponse, error) {
 	const (
 		Method = "GET"
 	)
···
 		return nil, err
 	}
 
-	return us.client.Do(req)
+	return do[types.RepoIndexResponse](us, req)
 }
 
 func (us *UnsignedClient) Log(ownerDid, repoName, ref string, page int) (*http.Response, error) {