Add Xquik MCP registry entry

[kriptoburak]

Summary

• Add a new xquik MCP server definition for the Xquik remote MCP endpoint.
• Add Xquik to the README server table and increment the visible server count.

Checks

• Duplicate gate: no existing Xquik entries, PRs, or issues in openmodelsrun/mcp.
• PYTHONPATH=/tmp/openmodelsrun-mcp-pydeps python3 validate.py
• git diff --cached --check
• Xquik docs, MCP docs, API docs, and public skill source checked.
• Added-line safety scan passed.