docs: add reviewed X source packet guidance

[kriptoburak]

Summary

• Add an optional reviewed X source-packet lane to the market-social Skill.
• Use TweetClaw and Xquik exports as evidence for hooks, objections, FAQs, and audience language.
• Link Xquik and identify it accurately as a hosted, closed-source service independent of X Corp.
• Keep the Skill draft-only: no posting, replies, DMs, media uploads, monitors, webhooks, or giveaway draws.
• Repair remote installer failure handling under set -e and use the correct BASH_SOURCE[0] element.

Validation

• git diff --check
• bash -n install.sh uninstall.sh
• shellcheck install.sh
• Python compilation for all 4 scripts
• Markdown link validation for README and market-social Skill
• Clean install and uninstall in an isolated temporary home