FPSF Admin Dashboard

Foundation staff console — start minimal, wired up to exactly the admin capabilities the backend already exposes today. No user management, billing, or impersonation here yet — see foundation/todo.yml's "Admin dashboard" entry for the eventual full scope; this build doesn't reach for it.

• Membership Applications — approve/reject pending applications, retry ones stuck mid-flow.
• Spec Ingestion Flags — specs that failed front-matter validation and were excluded from the viewer.