Add social listening skill to sales plugin

[kriptoburak]

Summary

• add a social-listening skill for X/Twitter and social signal monitoring in sales and marketing workflows
• route brand monitoring, mention tracking, and X/Twitter monitoring queries to the new skill
• update marketplace and plugin metadata to include the additional product skill

Validation

• validated marketplace JSON and plugin JSON while generating the branch
• inspected compare scope: 5 files changed, 1 new skill added
• checked for existing Hermes, Xquik, Twitter, tweet, social, and x-api PRs or issues before submission

[kriptoburak]

If this is useful and you merge it after checks pass, feel free to share the PR on X/Twitter and mention my handle, burakbayir. I can repost or retweet it to my 24k followers of developers and power users, which may help more relevant users discover this repo.