Add debug logging for frontend dist and SPA fallback

backend/src/app.js

@@ -132,7 +132,24 @@ app.use(express.static('src/public'));
 const path = require('path');
 const frontendDistPath = path.join(__dirname, '../../frontend/dist');
 const fs = require('fs');
+
 if (fs.existsSync(frontendDistPath)) {
+  logger.info(`Frontend dist found at: ${frontendDistPath}`);
+  
+  // List files for debugging
+  try {
+    const files = fs.readdirSync(frontendDistPath);
+    logger.info(`Frontend dist files: ${files.join(', ')}`);
+    
+    const assetsPath = path.join(frontendDistPath, 'assets');
+    if (fs.existsSync(assetsPath)) {
+      const assetFiles = fs.readdirSync(assetsPath);
+      logger.info(`Frontend assets: ${assetFiles.length} files`);
+    }
+  } catch (err) {
+    logger.warn(`Could not read frontend dist: ${err.message}`);
+  }
+  
   // Serve static files with proper headers for SPA
   // Use middleware to set headers with access to request object
   app.use((req, res, next) => {
@@ -160,6 +177,8 @@ if (fs.existsSync(frontendDistPath)) {
       res.setHeader('X-Content-Type-Options', 'nosniff');
     },
   }));
+} else {
+  logger.warn(`Frontend dist NOT found at: ${frontendDistPath}`);
 }
 
 // Session middleware
@@ -200,6 +219,9 @@ app.use('/t', require('./routes/tracking.routes'));
 
 // SPA fallback: serve index.html for all non-API routes (must be after all routes)
 if (fs.existsSync(frontendDistPath)) {
+  const indexHtmlPath = path.join(frontendDistPath, 'index.html');
+  logger.info(`Frontend SPA fallback enabled: ${indexHtmlPath}`);
+  
   app.get('*', (req, res, next) => {
     // Skip API routes and tracking routes
     if (req.path.startsWith('/api') || req.path.startsWith('/t/') || req.path.startsWith('/health')) {
@@ -208,10 +230,31 @@ if (fs.existsSync(frontendDistPath)) {
         error: 'Endpoint not found',
       });
     }
+    
+    // Log SPA fallback
+    logger.info(`SPA fallback: serving index.html for ${req.path}`);
+    
     // Serve frontend SPA
-    res.sendFile(path.join(frontendDistPath, 'index.html'));
+    if (fs.existsSync(indexHtmlPath)) {
+      res.sendFile(indexHtmlPath, (err) => {
+        if (err) {
+          logger.error(`Failed to send index.html: ${err.message}`);
+          res.status(500).json({
+            success: false,
+            error: 'Failed to load frontend',
+          });
+        }
+      });
+    } else {
+      logger.error(`index.html not found at: ${indexHtmlPath}`);
+      res.status(500).json({
+        success: false,
+        error: 'Frontend not found',
+      });
+    }
   });
 } else {
+  logger.warn(`Frontend dist not found at: ${frontendDistPath}`);
   // 404 handler (if frontend not built)
   app.use((req, res) => {
     res.status(404).json({