Onboarding: can't switch Google account (no account picker + nearly invisible Log out)

Summary

During first-run onboarding it's very hard to pick the right Google account when you have more than one. Two related problems:

1. OAuth doesn't let you choose the account

Sign-in opens the default browser and silently reuses whatever Google session is already active there — no account picker is shown. If the auto-selected account is the wrong one, there's no way to change it from the setup window itself.

This looks like the Google OAuth authorization request is missing prompt=select_account. Adding it would force Google to show the account chooser every time and fixes this on its own.

2. The "Log out" button is nearly invisible

Logging out is the only way to switch accounts, but the "Log out" control is low-contrast grey-on-dark in the bottom-right corner of the welcome screen. I only found it by accident. Worth raising the contrast / making it more discoverable, since it's currently the sole escape hatch for the problem above.

Steps to reproduce

1. Be signed into Google in your default browser with account A active.
2. Start onboarding and sign in — account A gets auto-selected, no chooser.
3. You actually want account B → no way to change it in the setup window.
4. Logging out in the browser doesn't help (the app already holds account A's token).
5. The only fix is the hidden "Log out" button on the welcome screen, then sign in again.

Suggested fixes

• Add prompt=select_account to the Google OAuth request so the account chooser always appears.
• Increase the contrast / discoverability of the "Log out" button.

Environment

• PostHog Code v0.54.115
• Windows 11
• Default browser: Firefox

Locate the Google OAuth authorization request and the onboarding welcome screen; no file or test is named in the issue. Verify that the account chooser appears during sign-in and that the Log out control is visibly discoverable with sufficient contrast.