feat(sso): implement sso redirect

[SkyDev125]

Summary

• What changed:
  • Added an instance setting and environment variable "FLUXER_SSO_AUTO_REDIRECT" to automatically redirect unauthenticated users to SSO.
  • Implemented automatic redirection in AuthLoginLayout.tsx with a local bypass mechanism ?local=true.
  • Added API schema updates, an admin UI checkbox, and unit tests verifying redirect/bypass behaviors.
• Why it is correct:
  • The feature is fully wired from configuration to UI and uses an alreadyAttempted ref to prevent redirect loops.
  • Local login remains accessible by appending ?local=true to the URL.
• Risk:
  • Low (disabled by default). If a broken SSO config is enabled, standard email/password login is still accessible via the /login?local=true bypass URL.

Closes #1268

Verification

• Tests run:
  • fluxer_api: SsoFlow.test.ts passed, 34/34.
  • fluxer_app: AutoSsoRedirect.test.ts passed, 11/11.
  • packages/config: EnvironmentOverrides.test.ts passed, 15/15.
• Manual checks:
  • Verified new checkbox in SSO admin page functionality
  • Verified user can log-in without having to interact with log-in page (auto-redirect working)
  • Verified logging out doesnt automatically log you in back.
  • Verified everything comes through properly in the API
  • Verified URL Bypass in case no automatic redirection is desired.
• Screenshots or recordings:

Checklist

• I understand every change in this PR.
• I can explain what it does and why it is correct.
• I disclosed any LLM coding help below.

LLM Disclosure

OpenAI Codex assisted with the implementation and testing of the SSO Redirect feature.