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/test/examples/04-chord-state.ts

@@ -0,0 +1,37 @@
+// Expose a document through Chord.
+// Run from packages/durable:
+//   node --conditions=source --experimental-strip-types test/examples/04-chord-state.ts
+import { BACKGROUND_CONTEXT } from "@earendil-works/chord/context";
+import { createSession, defineDoc, MemoryStorage } from "../../src/index.ts";
+
+const context = BACKGROUND_CONTEXT;
+const session = createSession(new MemoryStorage());
+
+const Notes = defineDoc<{ text: string }>({
+	kind: "example.notes",
+	version: 1,
+	scope: "conversation",
+	history: "rewindable",
+	fork: "asOf",
+	initial: () => ({ text: "" }),
+});
+const chat = await session.commit(async (tx) => {
+	const conversation = await tx.createConversation({ ownership: { kind: "ownerless" } });
+	(await tx.doc(Notes, conversation.id)).text = "first";
+	return conversation;
+}, context);
+
+// documentState() never creates a document. It returns a hydrated read-only
+// Chord state bound to the current concrete incarnation.
+const notesState = await session.documentState(Notes, chat.id, context);
+if (notesState === undefined) throw new Error("notes are absent");
+const stopNotes = notesState.subscribe((value, _deliveryContext, delivery) => {
+	console.log("Chord notes:", delivery.kind, delivery.sequence, value);
+});
+await session.commit(async (tx) => {
+	(await tx.doc(Notes, chat.id)).text = "published through Chord";
+}, context);
+stopNotes();
+notesState.dispose();
+
+await session.close(context);