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/chord/src/services/state-internals.ts

@@ -0,0 +1,20 @@
+import type { Op } from "../delta/index.ts";
+import type { Context } from "../types.ts";
+
+export interface ReplicatedStateInternals {
+	readonly sequence: number;
+	readonly value: unknown;
+	publish(context: Context): void;
+	subscribe(listener: (ops: readonly Op[], sequence: number, context: Context) => void): () => void;
+}
+
+const sources = new WeakMap<object, ReplicatedStateInternals>();
+
+export function registerReplicatedStateInternals(value: object, internals: ReplicatedStateInternals): void {
+	sources.set(value, internals);
+}
+
+export function getReplicatedStateInternals(value: unknown): ReplicatedStateInternals | undefined {
+	if (typeof value !== "object" || value === null) return undefined;
+	return sources.get(value);
+}