Phase 5.x payment revamp + Xendit Stage-8 prep

- Backend wraps idn-finlogos npm at /assets/payment-icons/<slug>.svg with
  1y immutable cache. Mobile drops bundled SVGs (only placeholder remains)
  and fetches via flutter_cache_manager. payment_methods.icon is now a
  CSV of slugs; catalog emits icon_urls[]. CARDS tile renders Visa + MC +
  JCB side by side.
- Per-method min/max amount bounds (BIGINT, nullable). Picker greys out
  out-of-range tiles with subtitle; backend gates with INVALID_PAYMENT_AMOUNT
  (422). Defense in depth against stale-catalog clients.
- Xendit channel codes corrected from authoritative docs
  (BCA_VA -> BCA_VIRTUAL_ACCOUNT, CREDIT_CARD -> CARDS, ovo -> ovo-new,
  shopeepay -> shopee-pay, ...). 18 methods x 5 groups seeded with
  Xendit-published per-channel min/max.
- Re-runnable seed (ON CONFLICT DO NOTHING on payment_code + new unique
  index on group name). Operator CC edits never clobbered across re-runs.
  One-shot reset + inspect scripts under backend/.dev/.
- Customer redirect HTML pages at /payment/return/{success,failure},
  brand-styled with "Buka HaloBestie" CTA firing halobestie:// deeplink.
  URL scheme registered on Android (intent-filter w/ BROWSABLE on
  MainActivity) and iOS (CFBundleURLTypes). Waiting-payment poller still
  owns confirmation; deeplink just brings the activity to foreground.
- Control center payment-catalog page: min/max inputs + columns. Other
  CC pages restyled with new theme tokens (separate work, bundled here).

169/169 backend tests pass. See requirement/phase5-payment-revamp-2026-05-27.md
for the full revamp doc. Stage 8 (E2E) still pending: webhook URL routing
decision + two client_app follow-ups (legacy /chat/request removal,
extension Custom Tab).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

client_app/lib/features/payment/state/payment_catalog_provider.dart

@@ -2,18 +2,58 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../../../core/api/api_client_provider.dart';
 
 /// One row in the payment-method catalog (server-side: `payment_methods`).
+///
+/// `iconUrls` is the backend-resolved list of brand-SVG URLs for this method.
+/// Relative paths (e.g. `/assets/payment-icons/qris.svg`) are prepended with
+/// `ApiClient.baseUrl` by [PaymentIcon]. Composite tiles (e.g. credit card
+/// showing Visa + Mastercard + JCB) carry multiple entries. Empty list = no
+/// icon configured → the row renders the bundled placeholder.
+///
+/// `minAmount` / `maxAmount` are inclusive Rupiah bounds, either nullable
+/// (null = no bound). The picker greys out methods the current bill misses,
+/// and the backend enforces the same bounds defensively with
+/// `INVALID_PAYMENT_AMOUNT`.
 class PaymentMethodEntry {
   final String id;
   final String paymentCode;
   final String displayName;
-  final String? icon;
+  final List<String> iconUrls;
+  final int? minAmount;
+  final int? maxAmount;
 
   const PaymentMethodEntry({
     required this.id,
     required this.paymentCode,
     required this.displayName,
-    this.icon,
+    this.iconUrls = const [],
+    this.minAmount,
+    this.maxAmount,
   });
+
+  /// `null` when the method is usable at [amount]; otherwise a short reason
+  /// suitable as a tile subtitle (Indonesian, brand voice).
+  String? disabledReason(int amount) {
+    if (minAmount != null && amount < minAmount!) {
+      return 'min ${_rp(minAmount!)}';
+    }
+    if (maxAmount != null && amount > maxAmount!) {
+      return 'maks ${_rp(maxAmount!)}';
+    }
+    return null;
+  }
+}
+
+String _rp(int n) {
+  // Rp 10.000 (Indonesian thousand-separator). Matches the picker's other
+  // amount formatting via `formatRupiah` in core/constants.dart, kept local
+  // to avoid pulling that dependency into the catalog model.
+  final s = n.toString();
+  final buf = StringBuffer('Rp ');
+  for (var i = 0; i < s.length; i++) {
+    if (i > 0 && (s.length - i) % 3 == 0) buf.write('.');
+    buf.write(s[i]);
+  }
+  return buf.toString();
 }
 
 /// One group in the payment-method catalog (server-side:
@@ -50,11 +90,13 @@ const _kFallbackGroup = PaymentMethodGroup(
   id: 'fallback-paling-cepat',
   name: 'Paling Cepat',
   methods: [
+    // Fallback path renders the bundled placeholder (iconUrls empty) — the
+    // catalog endpoint being unreachable usually means the icon endpoint is
+    // too, so deferring to the placeholder is the safest signal.
     PaymentMethodEntry(
       id: 'fallback-qris',
       paymentCode: 'QRIS',
       displayName: 'QRIS',
-      icon: 'qris',
     ),
   ],
 );
@@ -74,11 +116,14 @@ final paymentCatalogProvider = FutureProvider<PaymentCatalog>((ref) async {
       final gm = g as Map<String, dynamic>;
       final methods = (gm['methods'] as List<dynamic>? ?? const []).map((m) {
         final mm = m as Map<String, dynamic>;
+        final iconUrlsRaw = mm['icon_urls'] as List<dynamic>? ?? const [];
         return PaymentMethodEntry(
           id: mm['id'] as String,
           paymentCode: mm['payment_code'] as String,
           displayName: mm['display_name'] as String,
-          icon: mm['icon'] as String?,
+          iconUrls: iconUrlsRaw.cast<String>(),
+          minAmount: (mm['min_amount'] as num?)?.toInt(),
+          maxAmount: (mm['max_amount'] as num?)?.toInt(),
         );
       }).toList(growable: false);
       return PaymentMethodGroup(