🔧 Update Admin Dashboard and Authentication Flow

✅ Updated Admin Dashboard URL:
- Changed the Admin Dashboard access path from `/admin` to `/manage` in multiple files for consistency.

✅ Enhanced Middleware Authentication:
- Updated middleware to protect new admin routes including `/manage` and `/dashboard`.

✅ Implemented CSRF Protection:
- Added CSRF token generation and validation for login and session validation routes.

✅ Introduced Rate Limiting:
- Added rate limiting for admin routes and CSRF token requests to enhance security.

✅ Refactored Admin Page:
- Created a new admin management page with improved authentication handling and user feedback.

🎯 Overall Improvements:
- Strengthened security measures for admin access.
- Improved user experience with clearer navigation and feedback.
- Streamlined authentication processes for better performance.

lib/auth.ts

@@ -0,0 +1,74 @@
+import { NextRequest } from 'next/server';
+
+// Server-side authentication utilities
+export function verifyAdminAuth(request: NextRequest): boolean {
+  // Check for basic auth header
+  const authHeader = request.headers.get('authorization');
+  
+  if (!authHeader || !authHeader.startsWith('Basic ')) {
+    return false;
+  }
+
+  try {
+    const base64Credentials = authHeader.split(' ')[1];
+    const credentials = atob(base64Credentials);
+    const [username, password] = credentials.split(':');
+    
+    // Get admin credentials from environment
+    const adminAuth = process.env.ADMIN_BASIC_AUTH || 'admin:default_password_change_me';
+    const [expectedUsername, expectedPassword] = adminAuth.split(':');
+    
+    return username === expectedUsername && password === expectedPassword;
+  } catch (error) {
+    return false;
+  }
+}
+
+export function requireAdminAuth(request: NextRequest): Response | null {
+  if (!verifyAdminAuth(request)) {
+    return new Response(
+      JSON.stringify({ error: 'Unauthorized' }), 
+      { 
+        status: 401, 
+        headers: { 
+          'Content-Type': 'application/json',
+          'WWW-Authenticate': 'Basic realm="Admin Access"'
+        } 
+      }
+    );
+  }
+  return null;
+}
+
+// Rate limiting for admin endpoints
+const rateLimitMap = new Map<string, { count: number; resetTime: number }>();
+
+export function checkRateLimit(ip: string, maxRequests: number = 10, windowMs: number = 60000): boolean {
+  const now = Date.now();
+  const key = `admin_${ip}`;
+  
+  const current = rateLimitMap.get(key);
+  
+  if (!current || now > current.resetTime) {
+    rateLimitMap.set(key, { count: 1, resetTime: now + windowMs });
+    return true;
+  }
+  
+  if (current.count >= maxRequests) {
+    return false;
+  }
+  
+  current.count++;
+  return true;
+}
+
+export function getRateLimitHeaders(ip: string, maxRequests: number = 10, windowMs: number = 60000): Record<string, string> {
+  const current = rateLimitMap.get(`admin_${ip}`);
+  const remaining = current ? Math.max(0, maxRequests - current.count) : maxRequests;
+  
+  return {
+    'X-RateLimit-Limit': maxRequests.toString(),
+    'X-RateLimit-Remaining': remaining.toString(),
+    'X-RateLimit-Reset': current ? Math.ceil(current.resetTime / 1000).toString() : Math.ceil((Date.now() + windowMs) / 1000).toString()
+  };
+}