docs(contrib): add Parallel Search MCP example

[georgeatparallel]

kagent already has a native RemoteMCPServer resource for public Streamable HTTP endpoints. This adds a small community example so users can register live web search and URL fetching without setting up an account or API key.

What changed

• Added a RemoteMCPServer manifest for https://search.parallel.ai/mcp.
• Documented installation, opt-in agent behavior, the web_search and web_fetch tools, and a status check.
• Kept existing agents, providers, and defaults unchanged.

Validation

• git diff --check
• Parsed the YAML and asserted its API version, kind, resource name, endpoint, and protocol.

I did not run the manifest against a live kagent cluster.

Disclosure: I work at Parallel.ai, which operates this MCP endpoint.