Migrate to SaaSKit

Audit existing auth and import it to SaaSKit. Then stop.

Guardrails

• MUST audit and export before any import.
• MUST store original org and user primary keys in external_id.
• MUST set sendInvitationEmail: false on every imported user.
• MUST NOT copy password hashes unless the Scalekit Solutions team does it.
• MUST keep a rollback feature flag through the first rollout window.
• MUST NOT write first-time login, callback, or logout. Name implement-saaskit instead.

Gotchas