Fix: Stabilize authentication system with default secrets and better error handling

backend/middleware/auth.js

@@ -20,8 +20,10 @@ exports.protect = asyncHandler(async (req, res, next) => {
     return next(new ErrorResponse('Not authorized: Neural token missing', 401));
   }
 
+  console.log(`[DEBUG_AUTH] Verifying token: ${token.substring(0, 10)}... (Length: ${token.length})`);
+
   try {
-    const decoded = jwt.verify(token, process.env.JWT_SECRET);
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'secret');
     req.user = await User.findById(decoded.id);
     
     if (!req.user) {

backend/public/chat.html

@@ -284,6 +284,14 @@
         async function init() {
             try {
                 const res = await fetch(`${API_BASE}/api/users/profile`, { headers: { 'Authorization': `Bearer ${token}` } });
+                
+                if (res.status === 401) {
+                    console.error("Neural link unauthorized. Clearing local storage.");
+                    localStorage.removeItem('token');
+                    window.location.href = '/auth?error=UNAUTHORIZED';
+                    return;
+                }
+
                 const data = await res.json();
                 if (data.success) {
                     const p = data.data.preferences || {};

backend/server.js

@@ -18,6 +18,11 @@ const { syncToCloud, restoreFromCloud } = require('./services/persistenceService
 
 dotenv.config();
 
+// Critical Environment Defaults
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'TITAN_CORE_BETA_SECRET_2026';
+process.env.JWT_EXPIRE = process.env.JWT_EXPIRE || '30d';
+process.env.JWT_COOKIE_EXPIRE = process.env.JWT_COOKIE_EXPIRE || '30';
+
 // Connect to Cloud Database
 connectDB();
 restoreFromCloud();