0d9005f changed start_profile_oauth to return (session_id, auth_url, port) and
updated the tests, but not its callers. The wizard still unpacked two values, so
every Antigravity connection raised ValueError inside _init_antigravity_oauth,
the handler swallowed it, and the authorization URL never appeared — the primary
onboarding flow has been dead since that commit.
Also stores the listener port as wizard.oauth_port, which the single-session
invariance test reads to prove that repeat "open browser" clicks reuse the
existing listener instead of binding a new one.
Both defects were caught only by tests that the headless run skips, which is why
they survived several reviews.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>