Add temporary Sentry test button (dev/test only)

Co-authored-by: Junie <junie@jetbrains.com>

src/components/__tests__/SentryTestButton.test.tsx

@@ -0,0 +1,30 @@
+import { render, screen } from '@testing-library/react';
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import * as Sentry from '@sentry/react';
+import { SentryTestButton, handleSentryTestErrorClick } from '../SentryTestButton';
+
+vi.mock('@sentry/react', () => ({
+  captureException: vi.fn(),
+  logger: { info: vi.fn() },
+  metrics: { count: vi.fn() },
+}));
+
+describe('SentryTestButton', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('is visible in the current (development/test) build', () => {
+    render(<SentryTestButton />);
+    expect(screen.getByRole('button', { name: 'Break the world' })).toBeInTheDocument();
+  });
+
+  it('sends a log and a metric to Sentry, then throws an intentional test error', () => {
+    expect(() => handleSentryTestErrorClick()).toThrow('This is your first error!');
+
+    expect(Sentry.logger.info).toHaveBeenCalledWith('User triggered test error', {
+      action: 'test_error_button_click',
+    });
+    expect(Sentry.metrics.count).toHaveBeenCalledWith('test_counter', 1);
+  });
+});