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/features/tbank-connection/model/sync.test.tsx

@@ -0,0 +1,114 @@
+import { act, renderHook, waitFor } from "@testing-library/react";
+import { HttpResponse, http } from "msw";
+import { describe, expect, it, vi } from "vitest";
+import { apiQueryClient, configureAuthClient } from "@/shared/api";
+import { createQueryWrapper } from "@/test/query";
+import { server } from "@/test/server";
+import {
+	type InvestmentScreen,
+	useTbankSync,
+	useTbankSyncStatus,
+} from "../index";
+import { commitTbankConnectionBoundary } from "./connection-boundary";
+
+describe("sync connection and session boundaries", () => {
+	it.each(["connection", "session"])(
+		"discards pending status and mutation after %s changes",
+		async (boundary) => {
+			let generation = 0;
+			configureAuthClient({
+				generation: () => generation,
+				accessToken: () => "synthetic",
+				refresh: async () => true,
+				clear: vi.fn(),
+			});
+			let release!: () => void;
+			const blocked = new Promise<void>((resolve) => {
+				release = resolve;
+			});
+			const accepted = {
+				id: "work",
+				scope: { screen: "accounts" },
+				now: "2026-09-25T12:00:00Z",
+			};
+			let started = 0;
+			let changed = false;
+			server.use(
+				http.post("*/api/v1/tbank-sync", async () => {
+					started += 1;
+					await blocked;
+					return HttpResponse.json(accepted, { status: 202 });
+				}),
+				http.get("*/api/v1/tbank-sync/:id", async () => {
+					const now = changed ? "2026-09-25T12:01:00Z" : accepted.now;
+					started += 1;
+					await blocked;
+					return HttpResponse.json({
+						...accepted,
+						now,
+						state: "succeeded",
+						errorCode: null,
+						progress: { total: 1, completed: 1, discovering: false },
+						resources: [],
+					});
+				}),
+			);
+			const { wrapper, queryClient } = createQueryWrapper();
+			const published: string[] = [];
+			const unsubscribe = queryClient.getQueryCache().subscribe((event) => {
+				if (event.query.queryKey[1] === "/api/v1/tbank-sync/{id}") {
+					const data = event.query.state.data as { now?: string } | undefined;
+					if (data?.now) published.push(data.now);
+				}
+			});
+			const { result } = renderHook(
+				() => ({
+					mutation: useTbankSync(),
+					status: useTbankSyncStatus("work"),
+				}),
+				{ wrapper },
+			);
+			const screen: InvestmentScreen = { screen: "accounts" };
+			let mutation!: Promise<unknown>;
+			act(() => {
+				mutation = result.current.mutation.mutateAsync({ body: screen });
+			});
+			const discarded = expect(mutation).rejects.toMatchObject({
+				name: "AbortError",
+			});
+			await waitFor(() => expect(started).toBe(2));
+			await act(async () => {
+				changed = true;
+				if (boundary === "connection")
+					commitTbankConnectionBoundary(queryClient, {
+						connected: false,
+						connectedAt: null,
+					});
+				else {
+					generation += 1;
+					queryClient.clear();
+				}
+				release();
+				await blocked;
+			});
+			await discarded;
+			expect(result.current.mutation.data).toBeUndefined();
+			const key = apiQueryClient.queryOptions(
+				"get",
+				"/api/v1/tbank-sync/{id}",
+				{ params: { path: { id: "work" } } },
+			).queryKey;
+			// A new request may start after a successful connection boundary; an old result cannot win it.
+			if (boundary === "session")
+				expect(queryClient.getQueryData(key)).toBeUndefined();
+			else
+				await waitFor(() =>
+					expect(queryClient.getQueryData(key)).toMatchObject({
+						now: "2026-09-25T12:01:00Z",
+					}),
+				);
+			expect(published).not.toContain(accepted.now);
+			unsubscribe();
+		},
+	);
+});