- app_settings table (PostgreSQL migration 000010, SQLite 000002)
- internal/settings repository (Get/Set/Ensure) wired into store.Repos
- secret generated with crypto/rand on first start and persisted; reused on restart
- drop required JWT_SECRET from env/config; app.New takes a TokenManager and
storage.Open takes the resolved secret (URL_SECRET still overrides)
- docs updated