Add logout function and ADMIN_PASSWORD environment validation

lib/auth.ts

@@ -22,6 +22,16 @@ export async function requireAdminAuth(request: NextRequest): Promise<NextRespon
  */
 export async function verifyAdminPassword(password: string): Promise<boolean> {
     const bcrypt = await import('bcryptjs');
+
+    // Validate that ADMIN_PASSWORD is set (security best practice)
+    if (!process.env.ADMIN_PASSWORD) {
+        console.error('SECURITY WARNING: ADMIN_PASSWORD environment variable is not set!');
+        // Fallback to default hash only in development
+        if (process.env.NODE_ENV === 'production') {
+            throw new Error('ADMIN_PASSWORD environment variable is required in production');
+        }
+    }
+
     const adminPasswordHash = process.env.ADMIN_PASSWORD || '$2b$10$SHOt9G1qUNIvHoWre7499.eEtp5PtOII0daOQGNV.dhDEuPmOUdsq';
     return bcrypt.compare(password, adminPasswordHash);
 }