[Feature Request] Add passkey and password authentication options to reduce login friction

**Bug Description**
Please provide better authentication options. Currently, you only support two: Google and email. My organization doesn't want to add Google accounts into the mix, so that option is unavailable to me. The problem with email auth is that it typically takes about 5 minutes from the time I request the email until the time it arrives in my inbox. Since nearly all of my work depends on Claude, this means that when Claude logs me out, I'm stuck waiting for an uncomfortably long time with nothing to do waiting for an email to arrive. I don't know what causes the delay, but I know that it's beyond my control, and since Anthropic offers no workable alternatives, you own the delay whether or not you cause it. If you were to implement passkeys and/or passwords, that would be far better.

**Environment Info**
- Platform: win32
- Terminal: windows-terminal
- Version: 2.1.263
- Feedback ID: 041a6adc-5c1a-4a2f-a4e7-903d1ea23945

**Errors**
```json
[]
```

The issue names no files, tests, or entry points. Start by reviewing the existing Google and email authentication flow, then clarify whether passkeys, passwords, or both are in scope. Done should provide the selected authentication option and verify that users can authenticate without waiting for an email.

索引モデルが issue の本文から書いたものです。