feat: tighten dashboard shell density

tests/ui/dashboard-shell.test.tsx

@@ -68,6 +68,15 @@ test("locks the rail to the viewport and makes the content pane independently sc
   expect(main).toHaveClass("md:h-full", "md:overflow-y-auto");
 });
 
+test("uses a narrow desktop rail and removes the max-width shell cap", () => {
+  const { container } = render(<DashboardShell>dashboard body</DashboardShell>);
+  const shellFrame = container.firstElementChild;
+  const rail = screen.getByRole("complementary", { name: "Dashboard rail" });
+
+  expect(shellFrame).not.toHaveClass("max-w-7xl");
+  expect(rail.className).toContain("md:w-[228px]");
+});
+
 test("redirects the root page to orders", () => {
   HomePage();