test(integration): select the group From address in the #569 spec

Extend 04-shared-identity's UI test to not just assert team@example.org is
offered but to actually select it as the sender and confirm it becomes the
active From identity, then hold on the composer so the selected group address is
visible in the recorded video. Adds selectComposerFrom / selectedComposerFrom
helpers.

integration/tests/04-shared-identity.spec.ts

@@ -1,7 +1,14 @@
 import { test, expect } from '@playwright/test';
 import { ACCOUNTS, GROUP } from './helpers/config';
 import { JmapClient } from './helpers/jmap';
-import { login, forceSync, openComposer, composerFromOptions } from './helpers/app';
+import {
+  login,
+  forceSync,
+  openComposer,
+  composerFromOptions,
+  selectComposerFrom,
+  selectedComposerFrom,
+} from './helpers/app';
 
 /**
  * Issue #569 — the composer's "From" dropdown should include identities from
@@ -41,7 +48,7 @@ test.describe('Composer From: shared/group identities (issue #569)', () => {
     expect(groupIdentityEmails).toContain(team.email);
   });
 
-  test('the composer From selector offers the group address', async ({ page }) => {
+  test('the composer From selector offers and can select the group address', async ({ page }) => {
     await login(page, member);
     // Shared accounts/identities are discovered from the JMAP session; give the
     // client a beat to settle them after the first render.
@@ -49,11 +56,21 @@ test.describe('Composer From: shared/group identities (issue #569)', () => {
 
     await openComposer(page);
 
-    // The group address alice can send as should be one of the From choices.
-    // If #569 is unaddressed the control collapses to her own address only and
-    // this poll times out — which is the point: it pins the expected behaviour.
+    // The group address the member can send as should be one of the From
+    // choices. If #569 were unaddressed the control would collapse to her own
+    // address only and this poll would time out — which is the point: it pins
+    // the expected behaviour.
     await expect
       .poll(async () => (await composerFromOptions(page)).join(' | '), { timeout: 15000 })
       .toContain(team.email);
+
+    // Pick the group address as the sender and confirm it becomes the selected
+    // From identity (not just a listed option).
+    await selectComposerFrom(page, team.email);
+    await expect.poll(() => selectedComposerFrom(page), { timeout: 5000 }).toContain(team.email);
+
+    // Hold on the composer so the final video frames clearly show the group
+    // address selected in the From field.
+    await page.waitForTimeout(2000);
   });
 });