[Feature]: Support for customized forwarding Tavily endpoint

[huaium]

Issue Checklist

• I understand that issues are for reporting problems and requesting features, not for off-topic comments, and I will provide as much detail as possible to help resolve the issue.
• I have checked the pinned issues and searched through the existing open issues, closed issues, and discussions and did not find a similar suggestion.
• I have provided a short and descriptive title so that developers can quickly understand the issue when browsing the issue list, rather than vague titles like "A suggestion" or "Stuck."
• The latest version of Cherry Studio does not include the feature I am suggesting.

Platform

macOS

Version

v1.0.6

Is your feature request related to an existing issue?

Present latest version of Cherry Studio uses Tavily official api host to implement web search functionality, however there are some third-party api providers that forward the official one to their own endpoint.

Desired Solution

Hope users can customize Tavily endpoint like what we did for model providers.

Alternative Solutions

No response

Additional Information

No response