Add Xquik remote MCP example

[kriptoburak]

Summary

• Add an examples/mcp/xquik-remote example for connecting fast-agent to a bearer-auth HTTP MCP server.
• Include a minimal interactive agent plus fast-agent.yaml using Authorization: Bearer ${XQUIK_API_KEY}.
• Document source-truth links and untrusted-result handling for public X/Twitter research.

Validation

• python3 -m py_compile examples/mcp/xquik-remote/agent.py
• Parsed examples/mcp/xquik-remote/fast-agent.yaml with PyYAML and verified the HTTP server, URL, bearer header, and disabled OAuth setting.
• Fetched https://xquik.com/.well-known/mcp.json and verified the remote MCP URL plus Authorization header contract.
• git diff --cached --check
• Public diff scan for private implementation terms and banned punctuation

Duplicate Check

• Searched open and closed PRs and issues in evalstate/fast-agent for Xquik, x-twitter, tweet, and Twitter.
• Local tree search found no existing Xquik example or integration.

[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.