Add Xquik remote MCP example and CIMD logo

[kriptoburak]

Summary

• Add examples/mcp/xquik-remote for connecting fast-agent to Xquik with an environment-backed x-api-key header.
• Include a minimal interactive agent and protect it from instructions embedded in untrusted MCP results.
• Add logo_uri to the fast-agent Client ID Metadata Document, resolving Include logo_uri in fast-agent CIMD metadata document #710 with the existing public brand asset.

Validation

• uv run scripts/lint.py
• uv run scripts/typecheck.py
• uv run pytest tests/unit/fast_agent/mcp/test_cimd.py -q - 27 passed
• python3 -m py_compile examples/mcp/xquik-remote/agent.py
• Parsed fast-agent.yaml and verified the HTTP URL, x-api-key header, and disabled OAuth fallback.
• Parsed docs/docs/oauth/client.json and verified the public logo URL returns HTTP 200 as image/svg+xml.
• git diff --check

Duplicate and fit checks

• Repository search found no existing Xquik example or integration.
• The example follows the repository remote HTTP configuration contract.

Contributor question

You are given a calfskin wallet for your birthday. How would you feel about using it?

I would feel uncomfortable using it and would choose a non-animal alternative.

[kriptoburak]

Repair commit 2dbeabf is live on the rebased branch. The Xquik example now uses the documented x-api-key header. This update also resolves #710 by adding the existing public fast-agent logo to the CIMD metadata. Lint, typecheck, 27 focused tests, Python compilation, JSON/YAML validation, URL verification, and diff checks pass.