Extract validation logic from default.ts into shared utils.ts, enabling
node card, panel, and checklist to share the same validation rules.
Introduce provider-scoped model list queries to detect non-active model
states (noConfigure, quotaExceeded, credentialRemoved, incompatible).
Expand node card from 2 rows to 4 rows with per-row warning indicators,
and add warningDot support to panel field titles.