There was a little glitch in the scraping protection where an errant regular expression briefly blocked all Firefox versions. Which is especially bad because I (the blog author) exclusively use Firefox, so I was blocking myself. The management apologizes for the problem (and generally allows much older Firefox versions than Chrome versions, as people seem to still use them on various platforms).
This should be fixed for you now. To my surprise, some legitimate versions of Firefox report 'rv:109.0' with a Firefox/<ver> version that is not 109 (along with all of the crawlers that have latched on to 'rv:109.0' as something they put in their User-Agent strings along with random old Firefox versions).
and I can confirm that I can now read your site using the native user agent string. (FWIW, I expect to upgrade to FF-128 within the next couple of months.)