Run a single warming pass on X — scroll the home feed, like 1-3 tweets, optionally repost one. First arg is an optional brand slug (defaults to default_brand in config/brand.json). Reads cadence from config/engagement-schedule.json, brand tunables (own handle, topic regex, parody-risk handles) from config/brand.json, and respects the daily budget + min-gap stored in ~/.social-skills/state/engagement-state.json. Use when the user says "warm x", "engage on x", or runs /x-warm. Also called by /warm-all on a schedule.
