Apply Team Override

Self-service: if the current user is active, email-verified, and their email appears in TEAM_OVERRIDE_EMAILS, set their plan to "team" (idempotent; never downgrades enterprise). Otherwise 403.

Backs the lifespan boot hook with an on-demand path so founders/ internal accounts can elevate themselves without waiting for a redeploy cycle. The rejection is deliberately generic so the endpoint never reflects an allowlist address or deployment configuration.