docs: align skill tool metadata

[kriptoburak]

Summary

• Align SKILL.md with the current post_publish, post_schedule, post_status, channel_hints, profile_list, and subreddit_list tool names.
• Update OpenClaw, MCP server, and lockfile version metadata to 3.0.0 so it matches package.json.
• Document optional TweetClaw source context for Twitter/X research before this server publishes approved channel variants.

Notes

This is separate from #2. It only updates published docs and release metadata plus an optional upstream source-context pattern.

Validation

• TypeScript build passed.
• Markdown link check passed for README and SKILL.
• Package dry run completed for version 3.0.0 with 59 files.
• JSON parse check passed for package.json, package-lock.json, and openclaw.plugin.json.
• npm audit reported 0 vulnerabilities.
• Git diff whitespace and public-safety scans passed.