feat(release): add phase10 tests, smoke load script, release checklist, and onboarding simulator flow

Backend/tests/env.test.ts

@@ -0,0 +1,25 @@
+import { afterEach, describe, expect, test } from 'bun:test';
+
+import { getBetterAuthBaseUrl, getFirstDefinedEnv } from '../utils/env';
+
+const ORIGINAL_ENV = { ...process.env };
+
+afterEach(() => {
+  process.env = { ...ORIGINAL_ENV };
+});
+
+describe('env helpers', () => {
+  test('getFirstDefinedEnv returns first set value', () => {
+    process.env.TEST_A = '';
+    process.env.TEST_B = ' value-b ';
+
+    expect(getFirstDefinedEnv('TEST_A', 'TEST_B')).toBe('value-b');
+  });
+
+  test('getBetterAuthBaseUrl prefers BETTER_AUTH_BASE_URL over legacy var', () => {
+    process.env.BETTER_AUTH_BASE_URL = 'http://base-url:4000';
+    process.env.BETTER_AUTH_URL = 'http://legacy:3000';
+
+    expect(getBetterAuthBaseUrl()).toBe('http://base-url:4000');
+  });
+});