fix: validate texture asset names server-side

lib/asset-classification.ts

@@ -1,15 +1,19 @@
 import { getAssetFamily } from './asset-naming'
 
-export type AssetCategory = 'color' | 'roughness' | 'normal' | 'metalness' | 'assets'
+export type AssetCategory = 'color' | 'diffuse' | 'roughness' | 'normal' | 'metalness' | 'opacity' | 'assets'
 
 export function classifyAssetCategory(filename: string): AssetCategory {
   const name = filename.replace(/\.[^.]+$/, '')
   const family = getAssetFamily(name.split('_')[0])
 
-  if (family === 'color' || family === 'diffuse') {
+  if (family === 'color') {
     return 'color'
   }
 
+  if (family === 'diffuse') {
+    return 'diffuse'
+  }
+
   if (family === 'roughness') {
     return 'roughness'
   }
@@ -22,5 +26,9 @@ export function classifyAssetCategory(filename: string): AssetCategory {
     return 'metalness'
   }
 
+  if (family === 'opacity') {
+    return 'opacity'
+  }
+
   return 'assets'
 }