chore(vendor): import pi 0.85.1

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: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/server/test/fixtures/stale-socket-server.mjs

@@ -0,0 +1,9 @@
+import { createServer } from "node:net";
+
+const path = process.argv[2];
+if (!path) throw new Error("Socket path argument is required");
+
+const server = createServer();
+server.listen(path, () => {
+	if (process.send) process.send("listening");
+});