Allows a user to add a password which automatically creates and email
identity to enable email + password authentication for OAuth-only
accounts.
Gated behind a feature flag: `enableAccountPassword`
When a user does not have an email identity, allow them to set a
password:
<img width="762" height="284" alt="Screenshot 2026-08-13 at 14 52 53"
src="https://github.com/user-attachments/assets/70b4883a-ed38-488a-a1b7-908caa112a0b"
/>
Password modal:
<img width="519" height="423" alt="Screenshot 2026-08-13 at 14 56 57"
src="https://github.com/user-attachments/assets/56ac370d-9e6c-4b05-986f-3aa9a51826c2"
/>
Email identity has been created, allow unlinking and/or updating email
address or password:
<img width="764" height="285" alt="Screenshot 2026-08-13 at 14 55 04"
src="https://github.com/user-attachments/assets/5d9d7692-f4e3-4638-958d-15fefad01333"
/>
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* OAuth-only accounts can set a password from Sign-in methods.
* Added password visibility controls, validation guidance, and success
or error feedback.
* Sign-in methods display the account email when available.
* **Updates**
* Renamed “Account identities” to “Sign-in methods” throughout account
preferences.
* Standardized password requirements across password setup and reset
forms.
* Setting a password refreshes the current session and signs out other
sessions.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
