feat: show cover images for all items in weekly digest

fix: /status shows '⏳ 等待中' when no API calls yet instead of '❌ 異常'

docs: update README with /status, /code, /digest commands

v1.1.0 — add /status, /code, /digest commands + weekly digest scheduler

Remove unnecessary 'read' tool from OpenClaw skill scope

v1.0.0 — add random feature, README, reset version

Initial release v1.5.0 — FANZA AV Discord Bot + OpenClaw Skill