添加@types/multer类型依赖

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/package.json

@@ -80,6 +80,7 @@
     "@types/bcrypt": "^5.0.2",
     "@types/express": "^4.17.21",
     "@types/jest": "^29.5.11",
+    "@types/multer": "^2.0.0",
     "@types/node": "^20.11.5",
     "@types/passport-jwt": "^4.0.1",
     "@types/passport-local": "^1.0.36",

pnpm-lock.yaml

@@ -92,6 +92,9 @@ importers:
       '@types/jest':
         specifier: ^29.5.11
         version: 29.5.14
+      '@types/multer':
+        specifier: ^2.0.0
+        version: 2.0.0
       '@types/node':
         specifier: ^20.11.5
         version: 20.19.25