init: 整合项目（dashboard + www + docs）

dashboard/backend/src/utils/jwt.js

@@ -0,0 +1,27 @@
+const jwt = require('jsonwebtoken');
+
+const JWT_SECRET = process.env.JWT_SECRET || 'dev-only-change-me-for-production';
+const JWT_ALGORITHM = 'HS256';
+const TOKEN_TTL_HOURS = 12;
+
+function createAccessToken(user) {
+  const now = Math.floor(Date.now() / 1000);
+  const payload = {
+    sub: user.id,
+    username: user.username,
+    is_super_admin: !!user.is_super_admin,
+    iat: now,
+    exp: now + TOKEN_TTL_HOURS * 3600,
+  };
+  return jwt.sign(payload, JWT_SECRET, { algorithm: JWT_ALGORITHM });
+}
+
+function decodeToken(token) {
+  return jwt.verify(token, JWT_SECRET, { algorithms: [JWT_ALGORITHM] });
+}
+
+function getTokenTtlSeconds() {
+  return TOKEN_TTL_HOURS * 3600;
+}
+
+module.exports = { createAccessToken, decodeToken, getTokenTtlSeconds, TOKEN_TTL_HOURS };