docs: add optional Xquik public X context

[kriptoburak]

Summary

• Add an optional Xquik public X context step to amazon-competitor-monitoring.
• Keep X findings separate from Amazon marketplace facts and use them only as supporting evidence.
• Normalize changed punctuation in the touched skill file to plain hyphen punctuation.

Duplicate And Policy Checks

• Memory ledger checked before outreach.
• Target PRs, issues, and code search had no existing Xquik entries.
• The only existing target PR is unrelated to this skill surface.
• Public text avoids badge links, ranking claims, private implementation details, and credential values.

Validation

• Git diff whitespace check passed.
• Selected skill installed successfully with the skills CLI from the local checkout.
• Xquik docs link returned HTTP 200 after redirect.
• Added public-text safety scan was clean.