Fix 404 for README-based section pages in Express router

Resolve directory README.html paths for nav links like 周易 and 中医宝典.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/index.js

@@ -115,27 +115,47 @@ if (!fs.existsSync(distPath)) {
   process.exit(1)
 }
 
-app.use(express.static(distPath, { index: false }))
+app.use(
+  express.static(distPath, {
+    index: ['index.html', 'README.html'],
+    extensions: ['html'],
+    redirect: true,
+  }),
+)
+
+function resolveHtmlPath(urlPath) {
+  const rel = decodeURIComponent(urlPath).replace(/^\//, '').replace(/\/$/, '') || 'index'
+  const candidates = [
+    path.join(distPath, `${rel}.html`),
+    path.join(distPath, rel, 'index.html'),
+    path.join(distPath, rel, 'README.html'),
+  ]
+
+  for (const candidate of candidates) {
+    if (fs.existsSync(candidate)) {
+      return candidate
+    }
+  }
+
+  return null
+}
 
 app.get('*', (req, res, next) => {
   if (req.path.includes('.')) {
     return next()
   }
 
-  const rel = req.path.replace(/^\//, '').replace(/\/$/, '') || 'index'
-  const candidates = [
-    path.join(distPath, `${rel}.html`),
-    path.join(distPath, rel, 'index.html'),
-    path.join(distPath, '404.html'),
-  ]
-
-  for (const candidate of candidates) {
-    if (fs.existsSync(candidate)) {
-      return res.sendFile(candidate)
-    }
+  const htmlPath = resolveHtmlPath(req.path)
+  if (htmlPath) {
+    return res.sendFile(htmlPath)
   }
 
-  return next()
+  const notFound = path.join(distPath, '404.html')
+  if (fs.existsSync(notFound)) {
+    return res.status(404).sendFile(notFound)
+  }
+
+  return res.status(404).send('Not Found')
 })
 
 app.listen(PORT, '0.0.0.0', () => {