Add Xquik MCP to the agent plugin list

[kriptoburak]

Summary

• Add Xquik MCP to the Web & Search section in both English and Chinese READMEs.
• Describe the current remote Streamable HTTP transport, 2-tool interface, and OAuth 2.1 or API-key authentication.
• Link the canonical Xquik repository.

Independent repository fix

Both READMEs said the project used CC0-1.0, but the committed LICENSE file is MIT. This PR corrects the English and Chinese license notices to match the repository's actual license.

Validation

• Confirmed the canonical Xquik repository and MCP documentation return HTTP 200.
• Confirmed server.json identifies Streamable HTTP, 2 tools, and OAuth 2.1.
• Confirmed the unauthenticated MCP endpoint returns the expected HTTP 401.
• Confirmed exactly 1 Xquik entry exists in each README with matching links and tags.
• Confirmed both README license notices match the MIT LICENSE file.
• Ran git diff --check upstream/main...HEAD.
• Audited all issues, comments, reviews, threads, checks, commits, and existing entries; no duplicate or pending feedback exists.

Xquik is an independent third-party service. Not affiliated with X Corp. "Twitter" and "X" are trademarks of X Corp.

[kriptoburak]

I consolidated the repair into signed commit 8c19f4a. The bilingual Xquik entries reflect the current remote Streamable HTTP transport, 2-tool interface, and OAuth 2.1 or API-key authentication. Independently, both README license notices now match the committed MIT license instead of CC0-1.0. The canonical repository and MCP docs return HTTP 200, bilingual parity and license consistency pass, and the PR is exactly 1 verified commit. A full README audit still finds 8 unrelated pre-existing dead links; this change adds none.