AC:\n- README badge shows 0.2.0 and highlights cloud fallback, quotas, web search.\n- Configuration docs and sample config cover list TTL, quotas, context window, and updated env guidance.\n- Troubleshooting docs explain authentication fallback and rate limit recovery.\n\nTests:\n- Attempted 'cargo xtask lint-docs' (command unavailable: no such command: xtask).
Acceptance Criteria:\n- header shows hourly/weekly usage with colored thresholds\n- :limits command prints persisted usage data and quotas\n- token usage survives restarts and emits 80%/95% toasts Test Notes:\n- cargo test -p owlen-core usage
