📦 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/aria-query/lib/etc/roles/dpub/docEndnoteRole.js

@@ -0,0 +1,33 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var docEndnoteRole = {
+  abstract: false,
+  accessibleNameRequired: false,
+  baseConcepts: [],
+  childrenPresentational: false,
+  nameFrom: ['author'],
+  prohibitedProps: [],
+  props: {
+    'aria-disabled': null,
+    'aria-errormessage': null,
+    'aria-expanded': null,
+    'aria-haspopup': null,
+    'aria-invalid': null
+  },
+  relatedConcepts: [{
+    concept: {
+      name: 'rearnote [EPUB-SSV]'
+    },
+    module: 'EPUB'
+  }],
+  requireContextRole: ['doc-endnotes'],
+  requiredContextRole: ['doc-endnotes'],
+  requiredOwnedElements: [],
+  requiredProps: {},
+  superClass: [['roletype', 'structure', 'section', 'listitem']]
+};
+var _default = exports.default = docEndnoteRole;