📦 添加虚拟环境和启动脚本

新增:
- backend/venv/ - Python 虚拟环境
- backend/start.sh - 启动脚本（使用虚拟环境）
- backend/requirements.txt - 依赖列表
- .gitignore - 忽略虚拟环境和缓存文件

说明:
- 每个项目使用独立虚拟环境
- 避免依赖冲突
- 启动脚本自动创建和激活虚拟环境

frontend/node_modules/webpack/schemas/plugins/LoaderOptionsPlugin.json

@@ -0,0 +1,27 @@
+{
+  "title": "LoaderOptionsPluginOptions",
+  "type": "object",
+  "additionalProperties": true,
+  "properties": {
+    "debug": {
+      "description": "Whether loaders should be in debug mode or not. debug will be removed as of webpack 3.",
+      "type": "boolean"
+    },
+    "minimize": {
+      "description": "Where loaders can be switched to minimize mode.",
+      "type": "boolean"
+    },
+    "options": {
+      "description": "A configuration object that can be used to configure older loaders.",
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "context": {
+          "description": "The context that can be used to configure older loaders.",
+          "type": "string",
+          "absolutePath": true
+        }
+      }
+    }
+  }
+}