FastItemLevel

Handle new 12.0 secure-tooltip secret value cases by avoiding raw UnitGUID() as table keys. Introduces GetSafeUnitCacheKey and IsSecretValue to prefer Name-Realm (with fall back to GUID when safe), an activeInspectKey to correlate NotifyInspect/INSPECT_READY, and switches cached/pending maps to use the safe cache key. Also adds safety checks around UnitExists/NotifyInspect and ensures ClearInspectPlayer is called after inspect.