feat(events): harden registration checkout lifecycle

apps/payments/models.py

@@ -81,6 +81,12 @@ class Payment(BaseModel):
         FAILED = 3, "Failed"
         CANCELED = 4, "Canceled"
 
+    class RefundStatusChoices(models.TextChoices):
+        NONE = "none", "No refund required"
+        PENDING = "pending", "Refund pending"
+        SUCCEEDED = "succeeded", "Refund completed"
+        MANUAL_REVIEW = "manual_review", "Refund needs review"
+
     user  = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='payments', editable=False)
     event = models.ForeignKey(Event, on_delete=models.PROTECT, related_name='payments', editable=False)
 
@@ -104,6 +110,24 @@ class Payment(BaseModel):
     card_pan = models.CharField(max_length=32, null=True, blank=True, editable=False)
     card_hash = models.CharField(max_length=128, null=True, blank=True, editable=False)
     verified_at = models.DateTimeField(null=True, blank=True, editable=False)
+    gateway_paid_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_attempts = models.PositiveSmallIntegerField(default=0, editable=False)
+    verification_last_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_next_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_lease_until = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_dispatch_expires_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_manual_review_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_status = models.CharField(
+        max_length=20,
+        choices=RefundStatusChoices.choices,
+        default=RefundStatusChoices.NONE,
+        editable=False,
+    )
+    refund_attempts = models.PositiveSmallIntegerField(default=0, editable=False)
+    refund_last_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_next_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_reference = models.CharField(max_length=64, null=True, blank=True, editable=False)
+    refund_last_error = models.CharField(max_length=255, blank=True, default='', editable=False)
 
     class Meta:
         constraints = [
@@ -127,5 +151,24 @@ class Payment(BaseModel):
         """Human-readable label for the payment status."""
         return self.get_status_display()
 
+    @property
+    def verification_state(self):
+        """Server-owned verification state for callback and support screens."""
+        if self.status == self.OrderStatusChoices.PAID or self.verified_at is not None:
+            return "verified"
+        if self.status == self.OrderStatusChoices.FAILED:
+            return "failed"
+        if self.status == self.OrderStatusChoices.CANCELED:
+            return "canceled"
+        if self.verification_manual_review_at is not None or not self.authority:
+            return "manual_review"
+
+        now = timezone.now()
+        if self.verification_lease_until and self.verification_lease_until > now:
+            return "checking"
+        if self.verification_next_attempt_at:
+            return "retry_scheduled"
+        return "awaiting_verification"
+
     def __str__(self):
         return f"{self.user.email}:{self.event} - {self.get_status_display()}"