feat: update finance manager and fix some issue

src/backend/item_manager/settings.py

@@ -40,6 +40,7 @@ INSTALLED_APPS = [
     "rest_framework",
     "corsheaders",
     "items",
+    "finance",
 ]
 
 MIDDLEWARE = [
@@ -141,6 +142,9 @@ USE_TZ = True
 STATIC_URL = "static/"
 STATIC_ROOT = BASE_DIR / "staticfiles"
 
+MEDIA_URL = "/media/"
+MEDIA_ROOT = BASE_DIR / "media"
+
 # 安全设置（生产环境）
 SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
 SECURE_SSL_REDIRECT = False  # 如果使用HTTPS，设置为True