`incorrect-bytes-format` XSL transformation is too slow on large XMIR files

I'm getting performance warnings when running lints against eo-runtime:

[WARNING] XSL transformation 'incorrect-bytes-format' took 174ms, whereas threshold is 100ms

What happens: The selector //o[normalize-space(string-join(text(), '')) != ''] materializes and concatenates all text node content for every <o> element in the document. Then for each match, matches($bytes, '^(--|[0-9A-F]{2}(-|(-[0-9A-F]{2})+))$') applies a complex alternation regex. On large XMIR with many byte-carrying elements the string-join + normalize-space + regex evaluation adds up significantly.

What should happen: The transformation completes within the 100ms threshold. Using //o[text()] as the initial selector (elements with any text node) before materializing would narrow the candidate set. The regex itself could also be simplified.