Add onboarding for parallel agents (#52940)

Release Notes:

- N/A

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Co-authored-by: Eric Holk <eric@zed.dev>
Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
Co-authored-by: Katie Geer <katie@zed.dev>
a0d0195ca9Danilo Leal committed on 4/8/2026, 1:05:43 AM· committed by GitHubparentbf9cea6
26 files changedLine totals unavailable