Add optional TweetClaw X/Twitter research workflow

[kriptoburak]

Summary

Adds an optional TweetClaw companion workflow for OpenClaw users who use Posta for social scheduling but need X/Twitter research, reply discovery, monitors, and source tweet IDs before drafting or scheduling posts.

What Changed

• Documents optional @xquik/tweetclaw setup in the OpenClaw install path.
• Adds a Posta skill section that separates TweetClaw X/Twitter research and approval-gated actions from Posta drafts, scheduling, publishing, media uploads, and analytics.
• Adds a workflow example that turns TweetClaw source notes into a reviewed Posta X/Twitter draft while keeping source evidence out of public captions.

Validation

• git diff --check
• bash -n skills/posta/scripts/posta-api.sh
• python3 -m py_compile skills/posta/scripts/sanitize_json.py
• jq empty openclaw.plugin.json .claude-plugin/plugin.json .claude-plugin/marketplace.json
• Local Markdown link check for changed files
• Heading numbering check for changed docs
• Added-line em dash and sensitive-string scans
• npm view @xquik/tweetclaw version returned 1.6.31
• TweetClaw GitHub, xquik.com, and target repo links returned OK; npm package page returned expected bot-protection 403 while npm metadata succeeded