feat(account): wrap portfolio sections in Mantine Accordion

All portfolio sections (stocks, bonds, other, cash, recent operations,
recent events) are now collapsible via Mantine Accordion. Sections
expand by default. Accordion control label uses h2 size to match
previous Section headings. Panel horizontal padding removed.
Smooth hover transition added. Removed unused Section component.
Updated lazy-route bundle baseline for account chunk.

src/pages/account/ui/AccountPage.test.tsx

@@ -154,9 +154,9 @@ describe("AccountPage states", () => {
 				"T-Bank временно недоступен. Показан последний успешный снимок.",
 			),
 		).toBeInTheDocument();
-		expect(screen.getByRole("heading", { name: "Акции" })).toBeInTheDocument();
+		expect(screen.getByRole("button", { name: "Акции" })).toBeInTheDocument();
 		expect(
-			screen.getByRole("heading", { name: "Облигации" }),
+			screen.getByRole("button", { name: "Облигации" }),
 		).toBeInTheDocument();
 		const positions = screen
 			.getAllByText(/Вторая|Первая/)