feat(ui-migration): 源数据加载与校验

读取 gameabc_{Object,Layer,GroupList,Image}.json, 跳过 {} 占位槽,
校验多帧图的网格与帧数一致(不符即显式抛错, 不兜底)。
真实数据回归护栏: 991 对象 / 55 界面 / 80 组 / 439 图 / 139 多帧图。
引入 pngjs devDep 供后续切图使用(仅迁移工具, 不进框架运行时)。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

cocoscreator_projects/package-lock.json

@@ -10,6 +10,7 @@
       "devDependencies": {
         "@types/node": "^26.0.1",
         "@types/ws": "^8.18.1",
+        "pngjs": "^7.0.0",
         "tsx": "^4.22.4",
         "typescript": "^6.0.3",
         "ws": "^8.21.0"
@@ -504,6 +505,15 @@
         "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
       }
     },
+    "node_modules/pngjs": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmmirror.com/pngjs/-/pngjs-7.0.0.tgz",
+      "integrity": "sha512-LKWqWJRhstyYo9pGvgor/ivk2w94eSjE3RGVuzLGlr3NmD8bf7RcYGze1mNdEHRP6TRP6rMuDHk5t44hnTRyow==",
+      "dev": true,
+      "engines": {
+        "node": ">=14.19.0"
+      }
+    },
     "node_modules/tsx": {
       "version": "4.22.4",
       "resolved": "https://registry.npmmirror.com/tsx/-/tsx-4.22.4.tgz",