feat: add endpoints to list and read log files; enhance log retrieval functionality

server/index.cjs

@@ -338,7 +338,7 @@ app.get('/api/config', (_req, res) => {
 })
 
 /**
- * Get recent logs (dev/debug only)
+ * Get recent logs from memory (dev/debug only)
  * GET /api/logs?limit=100&level=debug|info|warn|error&q=keyword
  */
 app.get('/api/logs', (req, res) => {
@@ -360,6 +360,70 @@ app.get('/api/logs', (req, res) => {
   res.json({ count: sliced.length, items: sliced })
 })
 
+/**
+ * List all log files in logs directory
+ * GET /api/logs/files
+ */
+app.get('/api/logs/files', (req, res) => {
+  if (!LOG_EXPOSE_API) {
+    return res.status(403).json({ error: 'FORBIDDEN', message: 'Log API disabled. Set LOG_EXPOSE_API=true to enable.' })
+  }
+  try {
+    const files = fs.readdirSync(LOG_DIR)
+      .filter(f => f.startsWith('LOGS_') && f.endsWith('.log'))
+      .map(f => {
+        const stats = fs.statSync(path.join(LOG_DIR, f))
+        return {
+          filename: f,
+          size: stats.size,
+          modified: stats.mtime,
+          path: `/api/logs/files/${f}`
+        }
+      })
+      .sort((a, b) => b.modified - a.modified)
+    res.json({ count: files.length, files })
+  } catch (e) {
+    logError('logs.files.error', { message: e?.message })
+    res.status(500).json({ error: 'READ_ERROR', message: e?.message || 'Failed to read log files' })
+  }
+})
+
+/**
+ * Read specific log file
+ * GET /api/logs/files/:filename
+ */
+app.get('/api/logs/files/:filename', (req, res) => {
+  if (!LOG_EXPOSE_API) {
+    return res.status(403).json({ error: 'FORBIDDEN', message: 'Log API disabled. Set LOG_EXPOSE_API=true to enable.' })
+  }
+  try {
+    const { filename } = req.params
+    
+    // SECURITY: VALIDATE FILENAME TO PREVENT DIRECTORY TRAVERSAL
+    if (!filename.match(/^LOGS_\d{8}\.log$/)) {
+      return res.status(400).json({ error: 'INVALID_FILENAME', message: 'Invalid log filename format' })
+    }
+    
+    const filePath = path.join(LOG_DIR, filename)
+    
+    if (!fs.existsSync(filePath)) {
+      return res.status(404).json({ error: 'NOT_FOUND', message: 'Log file not found' })
+    }
+    
+    const content = fs.readFileSync(filePath, 'utf8')
+    const lines = content.split('\n').filter(Boolean)
+    
+    res.json({ 
+      filename, 
+      lines: lines.length, 
+      content: lines 
+    })
+  } catch (e) {
+    logError('logs.file.read.error', { message: e?.message, filename: req.params.filename })
+    res.status(500).json({ error: 'READ_ERROR', message: e?.message || 'Failed to read log file' })
+  }
+})
+
 /**
  * Update payment toggles at runtime (dev only)
  * POST /api/config