Why your `[^<]+` regex is silently breaking on React SSR output

Picture this. You've shipped a programmatic SEO site, a few thousand pages of templated content. Google flags 14 URLs as soft 404s. You write a quick diagnostic: hit each URL, fetch the SSR HTML, check for a few content markers (a price string, a state average, a section header). Confirm what's really rendering, fix what's missing, move on. That was the plan. Forty minutes in, my script told me 0 of 14 pages had any EIA price data rendered. None. I was about to dig into the data fetching layer w