feat: enable permission-aware subagents

pi-subagents/test/fixtures/e2e-probe-ext.mjs

@@ -0,0 +1,25 @@
+/**
+ * Real extension fixture for the end-to-end test. Loaded by pi-mono's actual
+ * DefaultResourceLoader via `additionalExtensionPaths`. Registers one tool,
+ * `e2e_probe`, that writes a marker file when executed so the test can prove
+ * the model was actually able to call it (not just that it appeared in a list).
+ *
+ * Plain ESM (.mjs) so node imports it without any TS transform step.
+ */
+import { writeFileSync } from "node:fs";
+import { Type } from "@sinclair/typebox";
+
+export default function (pi) {
+  pi.registerTool({
+    name: "e2e_probe",
+    label: "E2E Probe",
+    description: "Writes a marker file. Used only by the end-to-end test.",
+    parameters: Type.Object({
+      marker: Type.String({ description: "Absolute path of the marker file to write." }),
+    }),
+    async execute(_id, params) {
+      writeFileSync(params.marker, "probed");
+      return { content: [{ type: "text", text: `wrote ${params.marker}` }] };
+    },
+  });
+}