[grade=A] Welcome email for first purchases: order-independent classification + premium walkthrough

- invoice.paid classified welcome-vs-renewal via emailDeliveredAt (durable,
  webhook-order independent) through new classifySubscriptionEmail() - the old
  isNewLicense/row-existence signal broke under Stripe's real event order
  (subscription.created pre-creates the row before the first invoice).
- renderLicenseEmail() extracted pure; first purchases now get 'Welcome to
  DashCaddy Premium' with unlocks panel (SSO/Recipes/Swarm/auto-renew) and
  3-step getting-started; renewal copy byte-identical (test-pinned).
- 9 new tests (37 total): behavioral classifier coverage, rendered-content
  assertions both variants, store flag regression, mkdtemp-sandboxed.
- Codex judge: A, zero blockers (r5; prior rounds D-D-D-C drove the fixes).
  Verdict: run output 'A' with empty Blockers (direct codex exec, 2026-09-22).

test/license-classify.test.js

@@ -0,0 +1,53 @@
+import assert from 'node:assert';
+import fs from 'node:fs';
+import { test } from 'node:test';
+
+// Behavioral tests for the welcome-vs-renewal classification (the exact
+// decision invoice.paid makes), through the exported pure classifier.
+
+const { classifySubscriptionEmail } = await import('../src/licenseLogic.js');
+
+// Simulated invoice.paid behavior against progressively-delivered license
+// state — no SMTP, no Stripe, no handler spin-up required; this is the same
+// state machine deliverAndTrackLicenseEmail drives via updateLicense().
+test('classification behavior across the real webhook order', () => {
+  const uniq = `classify_${Date.now()}`;
+  const license = {
+    id: `lic_${uniq}`,
+    key: 'DC-20F00-0000D-NB3FN-S6HXJ-A7CA0',
+    customerId: `cus_${uniq}`,
+    subscriptionId: `sub_${uniq}`,
+    emailDeliveredAt: null
+  };
+
+  // State 1: license row exists (subscription.created already processed),
+  // no email ever delivered -> invoice.paid must send the WELCOME email.
+  assert.equal(classifySubscriptionEmail(license).extended, false,
+    'pre-created license with zero delivered emails = welcome');
+
+  // State 2: welcome email delivered (deliverAndTrackLicenseEmail sets this
+  // via updateLicense after SMTP 250). Next invoice.paid = renewal.
+  license.emailDeliveredAt = new Date().toISOString();
+  assert.equal(classifySubscriptionEmail(license).extended, true,
+    'license with a delivered email = extended/renewal');
+});
+
+test('classification survives missing/blank email state', () => {
+  assert.equal(classifySubscriptionEmail(null).extended, false,
+    'null license cannot have delivered mail -> welcome');
+  assert.equal(classifySubscriptionEmail({}).extended, false,
+    'missing field -> welcome');
+  assert.equal(classifySubscriptionEmail({ emailDeliveredAt: '' }).extended, false,
+    'blank timestamp -> welcome');
+  assert.equal(classifySubscriptionEmail({ emailDeliveredAt: '2026-09-22T00:00:00.000Z' }).extended, true,
+    'real timestamp -> extended');
+});
+
+// The server must call the classifier, not inline its own logic.
+test('server.js delegates classification to classifySubscriptionEmail', () => {
+  const src = fs.readFileSync(new URL('../src/server.js', import.meta.url), 'utf8');
+  assert.ok(src.includes('classifySubscriptionEmail(license).extended'),
+    'handler must use the shared classifier');
+  assert.ok(!src.includes('Boolean(license.emailDeliveredAt)'),
+    'no inline duplicate of the logic');
+});