Document an X/Twitter plugin example after deployment

[kriptoburak]

The README already has a ClawHub & Skills section for post-deployment capabilities. It would help Coolify users if that section included one concrete code-plugin example for X/Twitter workflows after their OpenClaw gateway is running.

Suggested short addition:

### X/Twitter Workflows

For tweet search, reply search, follower export, user lookup, media workflows, direct messages, monitors, webhooks, giveaway draws, and approval-gated post tweets or replies, install TweetClaw:

```bash
openclaw plugins install @xquik/tweetclaw
```

See [TweetClaw](https://github.com/Xquik-dev/tweetclaw) for setup details and current package metadata.

I am opening this as an issue instead of a PR because I could not find a license file in the repo. If you prefer a patch, I can send one in the README style.