chore: import upstream snapshot with attribution

packages/js-sdk/tests/connectionConfig.browser.test.ts

@@ -0,0 +1,24 @@
+import { afterEach, assert, test, vi } from 'vitest'
+
+afterEach(() => {
+  vi.resetModules()
+  vi.doUnmock('../src/utils')
+})
+
+test('sandbox_url keeps per-sandbox host in browser runtime', async () => {
+  vi.doMock('../src/utils', () => ({
+    runtime: 'browser',
+    runtimeVersion: 'test',
+  }))
+
+  const { ConnectionConfig } = await import('../src/connectionConfig')
+  const config = new ConnectionConfig()
+
+  assert.equal(
+    config.getSandboxUrl('sbx-test', {
+      sandboxDomain: 'e2b.app',
+      envdPort: 49983,
+    }),
+    'https://49983-sbx-test.e2b.app'
+  )
+})