Support Anthropic Web Fetch built-in tool

[DouweM]

Description

https://docs.claude.com/en/docs/agents-and-tools/tool-use/web-fetch-tool

This is equivalent to Gemini’s URL Context tool which we already support: https://ai.google.dev/gemini-api/docs/url-context

I like the Web Fetch name better though.

References

No response