tests: add Playwright event badge CRUD + interaction tests; add minimal V3 mocks and env helper; update presenter/badge smoke tests to use helpers; convert test locals to snake_case

tests/_helpers/env.ts

@@ -0,0 +1,17 @@
+/**
+ * Centralized test environment constants for Playwright and unit tests.
+ * Use snake_case names per project preference.
+ */
+export const test_base_url = 'http://demo.localhost:5173';
+export const dev_api_base = 'https://dev-api.oneskyit.com';
+export const demo_account_id = '_XY7DXtc9MY';
+export const demo_event_id = 'pjrcghqwert';
+
+export const TEST_ENV = {
+  test_base_url,
+  dev_api_base,
+  demo_account_id,
+  demo_event_id
+};
+
+export default TEST_ENV;