feat: add payment tracking for orders

- Add payment method selection (PayPal/Bar) to order form
- Store payment_method and payment_status in database
- Add payment status badges in admin orders view
- Add "mark as paid" functionality for admins
- PayPal account configurable via PAYPAL_ACCOUNT env variable
- Frontend loads PayPal account dynamically from /wawi/config endpoint
- Update email notifications to include payment method

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

wawi/static/style.css

@@ -198,6 +198,25 @@ input[type="text"], input[type="number"] {
 }
 .to-top:hover { transform: translateY(-2px); }
 
+.badge {
+  display: inline-block;
+  padding: 4px 10px;
+  border-radius: 4px;
+  font-size: 13px;
+  font-weight: 600;
+  white-space: nowrap;
+}
+.badge.success {
+  background: rgba(123, 213, 141, 0.2);
+  color: var(--ok);
+  border: 1px solid rgba(123, 213, 141, 0.4);
+}
+.badge.warning {
+  background: rgba(243, 213, 42, 0.2);
+  color: var(--accent);
+  border: 1px solid rgba(243, 213, 42, 0.4);
+}
+
 @media (max-width: 720px) {
   .actions { display: flex; gap: 6px; flex-wrap: wrap; }
   .btn.small { padding: 6px 8px; }