refactor: 移除自签名证书方案，服务只跑 HTTP

麦克风安全上下文改由部署方案解决：本机用 localhost，
对外部署挂 HTTPS 反向代理。删除 certs/、gen-cert.sh、
/cert 路由与 HTTPS server 分支，文档同步更新。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server.js

@@ -8,7 +8,6 @@
  * 模型：./models/ggml-small.bin（默认，较准）或 ggml-base.bin（较快，用 WHISPER_MODEL 切换）
  */
 const http = require('http');
-const https = require('https');
 const fs = require('fs');
 const os = require('os');
 const path = require('path');
@@ -17,7 +16,6 @@ const crypto = require('crypto');
 
 const ROOT = __dirname;
 const PORT = process.env.PORT || 8000;
-const HTTPS_PORT = process.env.HTTPS_PORT || 8443;
 const THREADS = String(Math.min(8, os.cpus().length || 4));
 const WHISPER = process.env.WHISPER_BIN || 'whisper-cli';
 const FFMPEG = process.env.FFMPEG_BIN || 'ffmpeg';
@@ -126,15 +124,6 @@ function handler(req, res) {
     });
     return;
   }
-  // ---- iOS 下载证书(浏览器打开会提示安装描述文件) ----
-  if (req.method === 'GET' && url.pathname === '/cert') {
-    fs.readFile(path.join(ROOT, 'certs', 'calx-cert.cer'), (e, data) => {
-      if (e) { res.writeHead(404); res.end('cert not found'); return; }
-      res.writeHead(200, { 'Content-Type': 'application/x-x509-ca-cert', 'Content-Disposition': 'attachment; filename="calx-cert.cer"' });
-      res.end(data);
-    });
-    return;
-  }
   if (req.method === 'GET' && url.pathname === '/health') {
     res.writeHead(200, { 'Content-Type': 'application/json' });
     res.end(JSON.stringify({ ok: true, model: path.basename(MODEL), modelExists: fs.existsSync(MODEL) }));
@@ -170,18 +159,5 @@ http.createServer(handler).listen(PORT, '0.0.0.0', () => {
   console.log(`\n乘法口诀服务已启动`);
   console.log(`  HTTP : http://localhost:${PORT}   http://${IP}:${PORT}`);
   console.log(`识别引擎: ${WHISPER}   模型: ${path.basename(MODEL)}  ${fs.existsSync(MODEL) ? '✅' : '❌ 模型不存在'}   线程: ${THREADS}   语法约束: ${HAS_GRAMMAR ? '✅' : '❌(用prompt)'}`);
+  console.log(`提示: 浏览器麦克风需要安全上下文——本机用 http://localhost:${PORT}；对外部署请挂在支持 HTTPS 的反向代理后面`);
 });
-
-// ---- HTTPS（iOS 用麦克风必需）----
-try {
-  const key = path.join(ROOT, 'certs', 'key.pem');
-  const cert = path.join(ROOT, 'certs', 'cert.pem');
-  if (fs.existsSync(key) && fs.existsSync(cert)) {
-    https.createServer({ key: fs.readFileSync(key), cert: fs.readFileSync(cert) }, handler)
-      .listen(HTTPS_PORT, '0.0.0.0', () => {
-        console.log(`  HTTPS: https://${IP}:${HTTPS_PORT}   (iOS 用这个，先访问 https://${IP}:${HTTPS_PORT}/cert 安装并信任证书)`);
-      });
-  } else {
-    console.log('  HTTPS: 未启用（缺少 certs/key.pem 或 certs/cert.pem）');
-  }
-} catch (e) { console.log('  HTTPS 启动失败:', e.message); }