User-Agent parser / UA classifier / browser detection / OS detection / bot detection / AI crawler identifier (GPTBot, ClaudeBot, PerplexityBot). Pure-local regex parser — detects browser (Chrome, Firefox, Safari, Edge, Opera, Vivaldi, Samsung), OS (Windows, macOS, iOS, Android, Linux, ChromeOS) with version, device type (desktop / mobile / tablet / bot), and identifies 32+ specific bots/crawlers. No upstream call.