Add web front-end and fix API issues

node_modules/concurrently/dist/lib/flow-control/flow-controller.d.ts

@@ -0,0 +1,13 @@
+import type { Command } from '../command.js';
+/**
+ * Interface for a class that controls and/or watches the behavior of commands.
+ *
+ * This may include logging their output, creating interactions between them, or changing when they
+ * actually finish.
+ */
+export interface FlowController {
+    handle(commands: Command[]): {
+        commands: Command[];
+        onFinish?: () => void | Promise<void>;
+    };
+}