chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/durable/src/tasks.ts

@@ -0,0 +1,8 @@
+import type { Task, TaskDefinition } from "./types.ts";
+
+/** Define an executable task. Register it in the registry so a Harness can run tasks of its kind. */
+export function defineTask<I, S extends { phase: string }, R, H extends object = object>(
+	definition: TaskDefinition<I, S, R, H>,
+): Task<I, S, R, H> {
+	return { definition };
+}