Send branded HTML emails and harden SMTP2GO webhooks.

Fix campaign stuck on sending under async queue, and stop UUID ValidationError when SMTP2GO tests send "Headers Unavailable".

site/messaging/tests.py

@@ -271,6 +271,8 @@ class CampaignSendTests(TestCase):
         self.assertEqual(len(mail.outbox), 1)
         self.assertEqual(mail.outbox[0].to, ["me@example.com"])
         self.assertTrue(mail.outbox[0].subject.startswith("[TEST]"))
+        self.assertTrue(mail.outbox[0].alternatives)
+        self.assertEqual(mail.outbox[0].alternatives[0][1], "text/html")
         # Recipients untouched
         self.assertEqual(
             self.campaign.messages.filter(status=Message.Status.DRAFT).count(), 1
@@ -300,6 +302,10 @@ class CampaignSendTests(TestCase):
         summary = mail.outbox[1]
         self.assertIn("Campaign sent:", summary.subject)
         self.assertEqual(summary.to, [self.user.email])
+        self.assertTrue(mail.outbox[0].alternatives)
+        self.assertEqual(mail.outbox[0].alternatives[0][1], "text/html")
+        self.assertIn("#00626c", mail.outbox[0].alternatives[0][0])
+        self.assertTrue(summary.alternatives)
 
 
 class Smtp2goEmailWebhookTests(TestCase):
@@ -443,6 +449,50 @@ class Smtp2goEmailWebhookTests(TestCase):
             )
             self.assertEqual(ok.status_code, 200)
 
+    def test_invalid_monica_header_does_not_500(self):
+        """SMTP2GO tests often send a non-UUID sample custom header."""
+        import json
+
+        url = reverse("messaging:email_webhook")
+        response = self.client.post(
+            url,
+            data=json.dumps(
+                {
+                    "event": "delivered",
+                    "rcpt": "nobody@example.com",
+                    "X-Monica-Message-Id": "Headers Unavailable",
+                    "email_id": "smtp2go-test-id",
+                }
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, 200)
+        data = response.json()
+        self.assertTrue(data["ok"])
+        self.assertFalse(data["matched"])
+        self.assertTrue(
+            ProviderEvent.objects.filter(event_type="delivered").exists()
+        )
+
+    def test_ui_event_label_aliases(self):
+        url = reverse("messaging:email_webhook")
+        response = self.client.post(
+            url,
+            data={
+                "event": "bounced",
+                "bounce": "soft",
+                "X-Monica-Message-Id": str(self.message.pk),
+            },
+        )
+        self.assertEqual(response.status_code, 200)
+        self.message.refresh_from_db()
+        self.assertEqual(self.message.status, Message.Status.BOUNCED)
+        self.assertTrue(
+            ProviderEvent.objects.filter(
+                message=self.message, event_type="bounce"
+            ).exists()
+        )
+
 
 class Smtp2goSmsWebhookTests(TestCase):
     def setUp(self):