fix: remove default dcrouter admin password

ts/opsserver/handlers/admin.handler.ts

@@ -43,14 +43,21 @@ export class AdminHandler {
   }
   
   private initializeDefaultUsers(): void {
-    // Add default admin user
+    const username = process.env.DCROUTER_ADMIN_USERNAME || 'admin';
+    const configuredPassword = process.env.DCROUTER_ADMIN_PASSWORD;
+    const password = configuredPassword || plugins.crypto.randomBytes(24).toString('base64url');
+
     const adminId = plugins.uuid.v4();
     this.users.set(adminId, {
       id: adminId,
-      username: 'admin',
-      password: 'admin',
+      username,
+      password,
       role: 'admin',
     });
+
+    if (!configuredPassword) {
+      console.warn(`DCRouter generated one-time admin password for ${username}: ${password}`);
+    }
   }
 
   /**
@@ -249,4 +256,4 @@ export class AdminHandler {
       name: 'adminIdentityGuard',
     }
   );
-}
+}