appview: use typed request helper for RepoBranchResponse

appview/state/pull.go

···
 		return pages.Unknown
 	}
 
-	resp, err := us.Branch(ownerDid, repoName, pull.PullSource.Branch)
+	result, err := us.Branch(ownerDid, repoName, pull.PullSource.Branch)
 	if err != nil {
 		log.Println("failed to reach knotserver", err)
-		return pages.Unknown
-	}
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		log.Printf("error reading response body: %v", err)
-		return pages.Unknown
-	}
-	defer resp.Body.Close()
-
-	var result types.RepoBranchResponse
-	if err := json.Unmarshal(body, &result); err != nil {
-		log.Println("failed to parse response:", err)
 		return pages.Unknown
 	}
 

knotclient/unsigned.go

···
 	return do[types.RepoTagsResponse](us, req)
 }
 
-func (us *UnsignedClient) Branch(ownerDid, repoName, branch string) (*http.Response, error) {
+func (us *UnsignedClient) Branch(ownerDid, repoName, branch string) (*types.RepoBranchResponse, error) {
 	const (
 		Method = "GET"
 	)
···
 		return nil, err
 	}
 
-	return us.client.Do(req)
+	return do[types.RepoBranchResponse](us, req)
 }
 
 func (us *UnsignedClient) DefaultBranch(ownerDid, repoName string) (*types.RepoDefaultBranchResponse, error) {