fix(ui): add cursor-pointer to base button variants

frontend/src/components/ui/button.test.tsx

@@ -0,0 +1,21 @@
+import { render, screen } from "@testing-library/react"
+import { describe, expect, it } from "vitest"
+import { Button } from "./button"
+
+describe("Button component", () => {
+  it("renders with a pointer cursor", () => {
+    render(<Button>Click me</Button>)
+    const button = screen.getByRole("button", { name: /click me/i })
+    expect(button).toHaveClass("cursor-pointer")
+  })
+
+  it("renders different variants with a pointer cursor", () => {
+    const { rerender } = render(<Button variant="outline">Outline</Button>)
+    let button = screen.getByRole("button", { name: /outline/i })
+    expect(button).toHaveClass("cursor-pointer")
+
+    rerender(<Button variant="destructive">Destructive</Button>)
+    button = screen.getByRole("button", { name: /destructive/i })
+    expect(button).toHaveClass("cursor-pointer")
+  })
+})