chore: update golangci-lint to v2.13.0

Migrate the deprecated gofumpt `extra-rules` to `extra.group-params`, as
the alias now also enables the new `clothe-returns` and `balance-calls`
rules. Disable SA4023, which hangs on go 1.27, see
https://github.com/golangci/golangci-lint/issues/6732.

Apply the resulting modernize fixes, mostly flattening embedded struct
literals and switching errors.As to errors.AsType.

Assisted-by: Claude:Opus 5

routers/api/actions/artifacts_utils.go

@@ -83,7 +83,7 @@ func parseArtifactItemPath(ctx *ArtifactContext) (string, string, bool) {
 	// it's formatted as {artifact_name}/{artfict_path_in_runner}
 	// runner in host mode on Windows, itemPath is joined by Windows slash '\'
 	itemPath := util.PathJoinRelX(ctx.Req.URL.Query().Get("itemPath"))
-	artifactName := strings.Split(itemPath, "/")[0]
+	artifactName, _, _ := strings.Cut(itemPath, "/")
 	artifactPath := strings.TrimPrefix(itemPath, artifactName+"/")
 	if !validateArtifactHash(ctx, artifactName) {
 		return "", "", false

routers/api/actions/runner/runner.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"net/http"
 	"slices"
+	"uuid"
 
 	runnerv1 "gitea.dev/actionslib/runner/v1"
 	"gitea.dev/actionslib/runner/v1/runnerv1connect"
@@ -23,7 +24,6 @@ import (
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/proto"
-	"uuid"
 )
 
 func NewRunnerServiceHandler() (string, http.Handler) {