feat: show persisted investment data and sync state

Consume the provided resource-envelope API snapshot. Preserve financial snapshots during
refresh, observe synchronization without importing, and fence late responses across
account and connection changes.

src/test/resource.ts

@@ -0,0 +1,21 @@
+import type { paths } from "@/shared/api";
+
+type Meta =
+	paths["/api/v1/brokerage-accounts"]["get"]["responses"][200]["content"]["application/json"]["meta"];
+function resource<T>(data: T, meta: Partial<Meta> = {}) {
+	return {
+		data,
+		meta: {
+			resourceKey: "fixture",
+			dataRevision: "1",
+			stateVersion: "1",
+			availability: data === null ? "missing" : "complete",
+			freshness: "fresh",
+			lastSuccessfulAt: "2026-08-14T00:00:00Z",
+			sync: { id: null, state: "idle", errorCode: null },
+			...meta,
+		} satisfies Meta,
+	};
+}
+
+export { resource };