Follow-Up

The list of students to follow up — fed by “+ Save to plan” from the student profile.

• Each entry: avatar, name, state, video, flags, note, add/update dates, ✕ button to remove.
• Empty state: “No students on follow-up list yet. Use "Save to plan" from a student's profile.”

Persisted in Postgres (table followups) via api/followup (GET/POST/DELETE).