SABnzbd client (queue, history, pause/resume, delete, retry) with lenient number decoding and API-key-safe errors. Downloads view polls while visible, shows queue and history, and supports pause, delete (with confirmation) and retry. Add dev/ with pinned Radarr/Sonarr/SABnzbd containers wired together for manual testing. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>