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

modules/charset/escape_stream.go

@@ -38,11 +38,9 @@ func escapeStream(locale translation.Locale, in io.Reader, out io.Writer, opts .
 		escaped:         &EscapeStatus{},
 		locale:          locale,
 		ambiguousTables: AmbiguousTablesForLocale(locale),
-		htmlChunkReader: htmlChunkReader{
-			in:      in,
-			readBuf: make([]byte, 0, 32*1024),
-		},
-		out: out,
+		in:              in,
+		readBuf:         make([]byte, 0, 32*1024),
+		out:             out,
 	}
 
 	if len(opts) > 0 {