Closes AI-244

This PR changes the approach for announcing skills support. It uses the
announcement toast, the same thing used for parallel agents, which
observes a specific version number to be displayed. I ended up
simplifying things a bit by thinking we could rely on documentation for
more detailed information (with more extensive paths and whatnot).

Release Notes:

- N/A

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Co-authored-by: Richard Feldman <richard@zed.dev>
Co-authored-by: MartinYe1234 <52641447+MartinYe1234@users.noreply.github.com>
Co-authored-by: Martin Ye <martinye022@gmail.com>