test(integration): dockerized webmail⇆Stalwart Playwright sync suite

Add an end-to-end integration harness that runs the webmail against a real
Stalwart mail server in Docker and drives it with Playwright, focused on the
mail/folder synchronisation behaviour (unread/total counters, folder-list
sync, account-scoped Unified Mailbox) that the unified-mailbox work touches.

- integration/ stack: Stalwart (declarative bootstrap: alice/bob/carol,
  submission + IMAP listeners, permissive CORS) + webmail (dev mode, so the
  browser's plaintext cross-origin JMAP calls aren't blocked by the prod CSP).
- Helpers: dependency-free SMTP submit client, JMAP client for seeding /
  inspecting server state, and page helpers (login, add/switch account,
  locale-independent folder-counter reads).
- Specs: login, single-account sync (receive/read/move/delete/folder-create/
  burst) and multi-account (per-account isolation + cross-account Unified
  Inbox aggregation + background-account delivery). 12 tests, all green.
- Add focused data-testid hooks to the mail UI (folder rows + counters, email
  list items, account switcher, composer) for stable selectors.
- Exclude examples/ and integration/ from tsconfig/eslint/.dockerignore.

integration/tests/global-setup.ts

@@ -0,0 +1,64 @@
+/**
+ * Brings the integration stack up before the suite runs:
+ *   1. fetch the arch-specific stalwart-cli (offline-friendly build input),
+ *   2. ensure integration/.env exists (compose credentials),
+ *   3. docker compose up -d --build --wait (Stalwart + webmail),
+ *   4. block until Stalwart JMAP and the webmail health endpoint answer.
+ *
+ * Set IT_NO_DOCKER=1 to skip container management entirely (useful when the
+ * stack is already running, e.g. during test authoring against `npm run dev`).
+ */
+import { execFileSync } from 'node:child_process';
+import { existsSync, copyFileSync } from 'node:fs';
+import path from 'node:path';
+import { JMAP_URL, WEBMAIL_URL, ACCOUNTS, ACCOUNT_PASSWORD } from './helpers/config';
+
+const INTEGRATION_DIR = path.resolve(__dirname, '..');
+const COMPOSE_FILE = path.join(INTEGRATION_DIR, 'docker-compose.yml');
+const ENV_FILE = path.join(INTEGRATION_DIR, '.env');
+
+function run(cmd: string, args: string[], cwd = INTEGRATION_DIR): void {
+  execFileSync(cmd, args, { cwd, stdio: 'inherit' });
+}
+
+async function waitFor(label: string, url: string, check: (r: Response) => boolean, timeoutMs = 240000): Promise<void> {
+  const deadline = Date.now() + timeoutMs;
+  for (;;) {
+    try {
+      const res = await fetch(url, { headers: { Authorization: 'Basic ' + Buffer.from(`${ACCOUNTS.alice.email}:${ACCOUNT_PASSWORD}`).toString('base64') } });
+      if (check(res)) return;
+    } catch {
+      /* not up yet */
+    }
+    if (Date.now() > deadline) throw new Error(`Timed out waiting for ${label} at ${url}`);
+    await new Promise((r) => setTimeout(r, 2000));
+  }
+}
+
+export default async function globalSetup(): Promise<void> {
+  if (process.env.IT_NO_DOCKER === '1') {
+    console.log('[global-setup] IT_NO_DOCKER=1 — skipping docker compose management');
+  } else {
+    console.log('[global-setup] fetching stalwart-cli');
+    run('bash', [path.join(INTEGRATION_DIR, 'stalwart', 'prepare-stalwart-cli.sh')]);
+
+    if (!existsSync(ENV_FILE)) {
+      console.log('[global-setup] creating integration/.env from .env.example');
+      copyFileSync(path.join(INTEGRATION_DIR, '.env.example'), ENV_FILE);
+    }
+
+    console.log('[global-setup] docker compose up -d --build --wait');
+    run('docker', [
+      'compose', '-f', COMPOSE_FILE, '--env-file', ENV_FILE,
+      'up', '-d', '--build', '--wait', '--wait-timeout', '300',
+    ]);
+  }
+
+  console.log('[global-setup] waiting for Stalwart JMAP');
+  await waitFor('Stalwart JMAP', `${JMAP_URL}/jmap/session`, (r) => r.ok);
+
+  console.log('[global-setup] waiting for webmail');
+  await waitFor('webmail', `${WEBMAIL_URL}/api/health`, (r) => r.ok, 240000);
+
+  console.log('[global-setup] stack ready');
+}