docs: add TweetClaw X research companion

[kriptoburak]

Summary

• Add TweetClaw as an optional public X/Twitter research and monitoring companion.
• Keep X campaign publication in Genviral when account capabilities allow it.
• Document the verified ClawHub source and npm fallback.
• Preserve Genviral scheduling, account-capability, and tracking ownership.

Independent Repository Fix

The updater used a check-then-touch lock file. Two processes could both pass the check before either touched the file, then concurrently overwrite the same skill-owned files.

This PR now:

• acquires the updater lock with one atomic mkdir;
• makes competing updater processes exit without writing;
• removes the lock on every normal exit;
• ignores updater state and lock artifacts in Git.

Validation

• Rebased on current main, including Genviral's current X posting support.
• Ran a real 2-process updater concurrency regression with mocked downloads.
• bash -n scripts/update-skill.sh
• bash -n scripts/genviral.sh
• shellcheck scripts/update-skill.sh scripts/genviral.sh
• Skill Creator quick_validate.py
• Verified TweetClaw's current public package and install source.
• git diff --check
• Rebuilt as 1 SSH-signed commit.

Xquik is an independent third-party service. Not affiliated with X Corp. "Twitter" and "X" are trademarks of X Corp.

[kriptoburak]

Rebuilt the branch on current main as 1 SSH-signed commit: 7d72974.

The earlier wording became stale after Genviral added X publishing support. The updated integration now keeps X campaign publication in Genviral and uses TweetClaw only for optional public research and monitoring. Installation uses the verified ClawHub source with an npm fallback.

I also fixed an independent updater race. The old check-then-touch lock allowed 2 updaters to enter together. Lock acquisition is now one atomic mkdir, updater artifacts are ignored, and a real 2-process regression confirmed that the second process exits without writing while the first completes and releases the lock.

Validation passed: Bash syntax, ShellCheck, skill validation, current package metadata, concurrency regression, whitespace checks, local SSH signature verification, and GitHub's public verified-signature check.