📦 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/hpack.js/bin/benchmark

@@ -0,0 +1,34 @@
+#!/usr/bin/env node
+var hpack = require('../');
+
+var options = {
+  table: { size: 1024 }
+};
+
+var compressor = hpack.compressor.create(options);
+
+var vector = [];
+for (var i = 0; i < 1024; i++) {
+  vector.push({
+    name: 'kind-of-big-header-name__',
+    value: 'not-so-small value yes!',
+    huffman: true,
+    neverIndex: true
+  });
+}
+compressor.write(vector);
+var input = compressor.read();
+
+console.time('decompressor');
+for (var i = 0; i < 2000; i++) {
+  var decompressor = hpack.decompressor.create(options);
+
+  decompressor.write(input);
+  decompressor.execute();
+  while (true) {
+    var chunk = decompressor.read();
+    if (!chunk)
+      break;
+  }
+}
+console.timeEnd('decompressor');