- internal/advisor/context.go: BuildContext assembles compact NetBox
summary (item count, category breakdown, recent 20 items)
- Caches result under sync.Mutex for defaultTTL=60s
- Stale cache returned on NetBox error rather than propagating failure
- internal/ai/types.go: add Tier3 TierConfig field to AIConfig
(required by AdvisorHandler for OpenRouter Claude Opus access)