feat: Initial SSO support with hwi/oauth-bundle

[jj2bw]

Goal: support Single-Sign On allowing people to use platforms of their choice to login, often big tech (Apple, Google, Microsoft...) but also Discord or any platform offering oauth2. This would also benefit of stronger authentication like MFA, passkeys, larger options for recoveries. Trade-off on privacy.

Implementation Following https://github.com/hwi/HWIOAuthBundle/blob/master/docs/index.md Currently test github only.

Work In Progress Limited testing as issues with local docker and CI (separate PR/issues) Current CI results with ci changes: https://github.com/jj2bw/rox/actions/runs/17012278568