Single Sign-On (#699)

* feat: implement Single Sign-On (SSO) functionality, enhance login provider management, and introduce a new features system.

* feat: reduced SSO providers to one, fixed SSO UI, stricter SSO SAML settings

* changing sso provider's name now updates better-auth's account schema

* fix types

* type fixes

* feat: hardcoding sso providerId

* fixed incorrect method call

* fixed idp initiated sso login; sso docs updated

* fixed type

* Added tests

* Potential fix for code scanning alert no. 698: Unused variable, import, function or class

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* Potential fix for code scanning alert no. 696: Unused variable, import, function or class

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* Potential fix for code scanning alert no. 695: Unused variable, import, function or class

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* Potential fix for code scanning alert no. 697: Unused variable, import, function or class

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* Potential fix for code scanning alert no. 694: Unused variable, import, function or class

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* Potential fix for code scanning alert no. 699: Useless conditional

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* refactor: remove unused `TOAST_TITLE_SUCCESS` import and adjust whitespace in SSO-related code.

* Removed id field

* added FAQ

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Co-authored-by: Rajat <[email protected]>
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Author: 3 people

AGENTS.md

@@ -8,6 +8,7 @@
 - In `apps/web` workspace, create a string first in `apps/web/config/strings.ts` and then import it in the `.tsx` files, instead of using inline strings.
 - When working with forms, always use refs to keep the current state of the form's data and use it to enable/disable the form submit button.
 - Check the name field inside each package's package.json to confirm the right name—skip the top-level one.
+- While working with forms, always use zod and react-hook-form to validate the form. Take reference implementation from `apps/web/components/admin/settings/sso/new.tsx`.
 
 ## Testing instructions