fix: address CodeRabbit review comments

- Add early return in updateAssetInCache when cacheKey resolves to undefined
- Fix test to use mapped node type to properly validate array cache behavior

Amp-Thread-ID: https://ampcode.com/threads/T-019c0bac-2144-73cb-a8d5-45146d0c2db9
Co-authored-by: Amp <amp@ampcode.com>

src/stores/assetsStore.ts

@@ -507,12 +507,13 @@ export const useAssetsStore = defineStore('assets', () => {
         cacheKey?: string
       ) {
         const category = cacheKey ? resolveCategory(cacheKey) : undefined
+        if (cacheKey && !category) return
+
         const categoriesToCheck = category
           ? [category]
           : Array.from(modelStateByCategory.value.keys())
 
         for (const cat of categoriesToCheck) {
-          if (!cat) continue
           const state = modelStateByCategory.value.get(cat)
           if (!state?.assets) continue