fix: preserve fallback charge cache invalidation

Core/ItemDetectionCacheSafety.lua

@@ -0,0 +1,25 @@
+-- Guda ClassicAPI ItemDetection cache safety
+-- Keep the optimized detection cache and the legacy per-slot charge cache in
+-- sync when ClassicAPI charge access is unavailable.
+-- Lua 5.0 compatible.
+
+local addon = Guda
+local ItemDetection = addon.Modules.ItemDetection
+if not ItemDetection then return end
+
+local FastClearCache = ItemDetection.ClearCache
+
+function ItemDetection:ClearCache()
+    if FastClearCache then
+        FastClearCache(self)
+    end
+
+    -- ItemDetectionClassicAPI keeps the original Vanilla charge-cache
+    -- invalidator behind this public method. With ClassicAPI charges present
+    -- it is a no-op; without them it clears the legacy bagID:slotID cache.
+    if self.InvalidateCharges then
+        self:InvalidateCharges(nil)
+    end
+end
+
+addon:Debug("ClassicAPI ItemDetection cache safety enabled")