feat(cli): allow custom timeout for streamable HTTP extensions

[Jazzcort]

Summary

Updates argument parsing to support a url timeout=<seconds> format, allowing users to override the default extension timeout.

Also want to add this feature to --with-extension (stdio extension), but not sure about what would be the best design of the format since the current format already included envs (Format: "ENV1=val1 ENV2=val2 command args..."). We can either add it at the end (after args...) like what I did for '--with-streamable-http-extension' or having a reserved env like EXT_TIMEOUT. The first approach might interfere the command if there are some edge cases, the later approach makes the behavior of passing customized timeout not consistent between --with-extension and --with-streamable-http-extension.

Type of Change

• Feature
• Bug fix
• Refactor / Code quality
• Performance improvement
• Documentation
• Tests
• Security fix
• Build / Release
• Other (specify below)

AI Assistance

• This PR was created or reviewed with AI assistance

Testing

goose session --with-streamable-http-extension "http://localhost:<port> timeout=<seconds>"

Use the above command to add a streamable http extension to the session with a customized timeout other than the default.
Maybe try eprintln!() the config to check if the timeout is successfully parsed.

[DOsinga]

I've resolve the merge conflicts in #6772 and will merge that one. thank you!

[Jazzcort]

Thank you so much for reviewing!