feat(pi): add read-only subagent attach view

modules/agents/pi/extensions/subagents/index.ts

@@ -6,7 +6,7 @@ import { SubprocessRpcRunner } from "./runner.ts";
 import { Supervisor } from "./supervisor.ts";
 import { milestoneNotification } from "./status.ts";
 import type { SpawnRequest, SubagentStatus } from "./types.ts";
-import { widget } from "./ui.ts";
+import { attachedChildView, widget } from "./ui.ts";
 
 let supervisor: Supervisor | undefined;
 let lastDiagnostics: Diagnostics = { warnings: [] };
@@ -230,6 +230,28 @@ export default function subagents(pi: ExtensionAPI) {
     },
   });
 
+  pi.registerCommand("subagent-attach", {
+    description: "Open a read-only attached view for a subagent id",
+    handler: async (args, ctx) => {
+      const id = args.trim();
+      if (!id) {
+        ctx.ui.notify("Usage: /subagent-attach <id>", "warning");
+        return;
+      }
+      const currentSupervisor = getSupervisor(ctx);
+      currentSupervisor.status(id);
+      await ctx.ui.custom<void>((tui, _theme, _keybindings, done) => attachedChildView({
+        status: () => currentSupervisor.status(id),
+        activity: () => currentSupervisor.activity(id),
+        onDetach: () => done(),
+        onChange: () => tui.requestRender(),
+      }), {
+        overlay: true,
+        overlayOptions: { width: "90%", maxHeight: "90%", minWidth: 60 },
+      });
+    },
+  });
+
   pi.registerCommand("subagent-wait", {
     description: "Wait for subagent ids separated by spaces",
     handler: async (args, ctx) => {