Add TweetClaw source intake guidance

[kriptoburak]

Summary

• Adds optional TweetClaw source-context guidance for X drafts that need live tweet, reply, follower, or media evidence.
• Keeps Typefully responsible for draft creation, scheduling, and publishing review.
• Normalizes touched separator punctuation to ASCII hyphens.

Validation

• Git diff whitespace check passed.
• Markdown link check passed for README.md and SKILL.md.
• Bash syntax check passed for scripts/typefully.sh.
• TweetClaw repository URL returned HTTP 200.