Add web front-end and fix API issues

node_modules/concurrently/dist/lib/flow-control/output-error-handler.d.ts

@@ -0,0 +1,18 @@
+import { Writable } from 'node:stream';
+import { Command } from '../command.js';
+import { FlowController } from './flow-controller.js';
+/**
+ * Kills processes and aborts further command spawning on output stream error (namely, SIGPIPE).
+ */
+export declare class OutputErrorHandler implements FlowController {
+    private readonly outputStream;
+    private readonly abortController;
+    constructor({ abortController, outputStream, }: {
+        abortController: AbortController;
+        outputStream: Writable;
+    });
+    handle(commands: Command[]): {
+        commands: Command[];
+        onFinish: () => void;
+    };
+}