Add Parallel Search MCP to the integration catalog

Desired Behavior

I'm George from Parallel. I'd like to make Parallel Search MCP available in the shared integration catalog so OpenHands users can add web search and page fetching through the normal MCP settings, without entering an API key.

PR #528 implements this catalog addition. It uses the existing no-auth Streamable HTTP connection at https://search.parallel.ai/mcp. Search queries and fetched URLs go to Parallel's hosted service. Anonymous access is free for light use and rate-limited.

The entry is opt-in and preserves existing providers, search defaults and saved server settings. Availability in released clients depends on the catalog release and the consumer updating its package.

Acceptance Criteria

• The shared catalog includes parallel-search with the documented no-auth Streamable HTTP endpoint.
• The generated JavaScript index and packaged Python catalog expose the same entry.
• OpenHands can install the entry through its existing MCP settings without requesting a credential or replacing a saved server.
• The search and page-fetch tools return useful results with source links, and invalid arguments surface as errors.
• Existing integrations and default search routing keep their current behavior.

Validation

The existing PR has recorded catalog, packaging and consumer test results, plus an anonymous search/fetch smoke test. The PR describes the commands and limits. The hosted UI was not exercised.

Would you review the catalog addition in #528?

Start with PR #528 and its recorded catalog, packaging, consumer tests, and anonymous search/fetch smoke-test results. Review the generated JavaScript index, packaged Python catalog, and existing MCP settings integration against the acceptance criteria; done means the entry works without credentials while preserving existing providers, defaults, and saved settings.