Prompt

Implement OAuth2/OpenID Connect authentication.

<application_type>
{SPA/mobile/server-side app}
</application_type>

<identity_providers>
{list of IdPs to support}
</identity_providers>

<security_requirements>
{compliance and security needs}
</security_requirements>

Implement:
1. Flow selection (code/implicit/etc)
2. Token handling and storage
3. Refresh token strategy
4. PKCE implementation
5. Scope management
6. Logout flows