## What changed
Move OpenAI API key, Amazon Bedrock, and Google Cloud Vertex AI options under “Sign in another way” during onboarding. Keep ChatGPT and device code sign-in on the main menu, and let `Esc` return from the alternative methods menu.
Guard activation keys across menu transitions so holding `Enter` or a numeric shortcut cannot advance through multiple steps or save a prefilled API key without a fresh confirmation.
## Testing
Add regression coverage for held activation keys and update onboarding tests and snapshots for submenu navigation, provider availability, and returning with `Esc`.
GitOrigin-RevId: b5aa56e48f10b490cc8f04b5d4288d21b76d2c61