chore: initialize my-pi extension bundle

extensions/fff-override.ts

@@ -0,0 +1,8 @@
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import fffExtension from "../node_modules/@ff-labs/pi-fff/src/index.ts";
+
+/** Load FFF as the bundle's canonical `find` and `grep` implementation. */
+export default function fffOverrideExtension(pi: ExtensionAPI): void {
+	process.env.PI_FFF_MODE = "override";
+	fffExtension(pi);
+}