feat: default web API calls to same origin

apps/web/test/api-base.test.js

@@ -0,0 +1,20 @@
+import { describe, expect, test } from 'bun:test';
+import { getApiBaseUrl } from '../src/lib/api-base.ts';
+
+describe('getApiBaseUrl', () => {
+  test('uses the configured API base when provided', () => {
+    expect(getApiBaseUrl('https://api.example.com/', 'https://app.example.com')).toBe(
+      'https://api.example.com',
+    );
+  });
+
+  test('defaults to the current window origin when no API base is configured', () => {
+    expect(getApiBaseUrl(undefined, 'https://app.example.com/')).toBe(
+      'https://app.example.com',
+    );
+  });
+
+  test('falls back to localhost in non-browser contexts without configuration', () => {
+    expect(getApiBaseUrl(undefined, undefined)).toBe('http://localhost:3001');
+  });
+});