fix: resolve frontend approval error and add invalid command handling

- Added missing approveMultiple function to updateApi
- Fixed API endpoint from /updates/bulk-approve to /updates/approve
- Enhanced invalid command handling in both Linux and Windows agents
- Agents now report unknown command types as failed commands back to server

aggregator-agent/cmd/agent/main.go

@@ -695,7 +695,20 @@ func runAgent(cfg *config.Config) error {
 					log.Printf("[Reboot] Error processing reboot command: %v\n", err)
 				}
 			default:
-				log.Printf("Unknown command type: %s\n", cmd.Type)
+				log.Printf("Unknown command type: %s - reporting as invalid command\n", cmd.Type)
+				// Report invalid command back to server
+				logReport := client.LogReport{
+					CommandID:       cmd.ID,
+					Action:          "process_command",
+					Result:          "failed",
+					Stdout:          "",
+					Stderr:          fmt.Sprintf("Invalid command type: %s", cmd.Type),
+					ExitCode:        1,
+					DurationSeconds: 0,
+				}
+				if reportErr := reportLogWithAck(apiClient, cfg, ackTracker, logReport); reportErr != nil {
+					log.Printf("Failed to report invalid command result: %v", reportErr)
+				}
 			}
 		}