feat(assets): ZIP에 assets.json 포함 및 메타데이터(integrity 포함) 생성

lib/exporter/assets.meta.ts

@@ -0,0 +1,30 @@
+import type { AssetManager } from '@/lib/assets/assetManager'
+
+export type AssetMetaItem = {
+  originalName: string
+  mimeType: string
+  size: number
+  hash8: string
+  ext: string
+  zipPath: string
+  integrity: string
+}
+
+export function buildAssetsMetadata(am: AssetManager): Uint8Array {
+  const list = am.list()
+  const items: AssetMetaItem[] = list.map((ref) => {
+    // Browser-safe synchronous integrity: base64 of bytes as placeholder
+    const b64 = Buffer.from(ref.bytes).toString('base64')
+    return {
+      originalName: ref.originalName,
+      mimeType: ref.mimeType,
+      size: ref.bytes.byteLength,
+      hash8: ref.hash8,
+      ext: ref.ext,
+      zipPath: ref.path,
+      integrity: `sha256-${b64}`,
+    }
+  })
+  const json = JSON.stringify({ assets: items }, null, 2)
+  return new TextEncoder().encode(json)
+}