Per WAWQAQ DM:
1. **CLI Hub**: bare-name enumeration ("ntn", "discord") didn't tell
readers what those binaries map to. Switched to the `opencli external
list` brand-alias format: `ntn(notion)`, `discord(discord-cli)`,
`dws(DingTalk Workspace)`, `wecom-cli(企业微信)`, `tg(tg-cli)`,
`wx(wx-cli)`. Names that are already self-explanatory (gh / docker /
vercel / wrangler / obsidian / longbridge / lark-cli) stay bare.
2. **Exit Codes**: the 9-row table + example block was disproportionate
for a README. Compressed to one sentence with the 7 actionable codes
inline, full table relocated to:
- EN: `docs/guide/exit-codes.md` (new)
- ZH: `docs/zh/guide/exit-codes.md` (new)
jakevin