List Guardrail Submissions

List team guardrail submissions. Returns only guardrails with a team_id.

Admins see all submissions. Non-admin users see submissions for teams they are a member of.

Status values: pending_review (team-registered, awaiting approval), active (approved), rejected.

Optional filters:

• status: pending_review | active | rejected
• team_id: filter by specific team (non-admins must be a member of that team)
• search: name/description