feat(outlook-addin): serve static files and prevent SPA routing for add-in paths

server/index.js

@@ -59,10 +59,15 @@ async function start() {
   app.use('/api/federation', calendarRoutes);
   app.get('/.well-known/redlight', wellKnownHandler);
 
+  // Serve Outlook Add-in static files (before SPA catch-all)
+  app.use('/outlook-addin', express.static(path.join(__dirname, '..', 'outlook-addin')));
+
   // Serve static files in production
   if (process.env.NODE_ENV === 'production') {
     app.use(express.static(path.join(__dirname, '..', 'dist')));
     app.get('*', (req, res) => {
+      // Don't serve SPA for outlook-addin paths
+      if (req.path.startsWith('/outlook-addin')) return res.status(404).end();
       res.sendFile(path.join(__dirname, '..', 'dist', 'index.html'));
     });
   }