Ruby client for the developer API of Misar.Blog (misar.blog), a hosted blogging platform. Publish or schedule Markdown articles, save and update drafts, group articles into series, read comment threads, reactions and follows, pull an analytics summary and live plan/quota state, generate SEO/AEO/GEO title suggestions, completions and AI cover images, search articles, profiles and tags, and build public iframe embed URLs — all 25 key-authenticated operations. Standard library only (net/http): mbk_ bearer auth, retry with exponential back-off, and a typed PlanLimitError carrying the upgrade URL.