Phase 5.x payment catalog + customer-app splash/register polish

Payment catalog (Phase 5.x — see requirement/phase5-payment-catalog-plan.md):
- New tables payment_method_groups + payment_methods with seed (3 groups,
  10 methods; GoPay seeded inactive pending Xendit channel confirmation).
- payment-catalog.service.js with two-layer cache (60s in-process + 1h
  Valkey) and config:invalidate pub/sub fanout. Mutator API + casing-
  tolerant findActiveMethodByCode for downstream validation.
- App-facing GET /api/client/payment-methods returns pre-grouped JSON,
  active-only, empty groups dropped server-side.
- POST /api/client/payment-requests now validates `method` against the
  catalog (INVALID_PAYMENT_METHOD 422) and stamps
  product_metadata.preferred_payment_code (upper-cased).
- Control-center /internal/payment-{groups,methods}{,/:id,/reorder}
  endpoints (full CRUD + idempotent reorder). New Payment Catalog page
  wired into the CC nav.
- Customer app renders the catalog as collapsible groups (first expanded)
  via paymentCatalogProvider; QRIS-only hardcoded fallback on 5xx so
  checkout never hard-fails. Replaces the hardcoded _PayMethod enum.
- 10 brand SVGs (~63KB) bundled in client_app/assets/payment_icons/ from
  github.com/hafidznoor/idn-finlogos. Xendit's per-channel media-asset
  pages were planned but found decommissioned during implementation —
  switched to idn-finlogos with the standard "channels-we-accept"
  trademark posture. See assets/payment_icons/README.md for the workflow
  to add new methods.
- 16 vitest cases covering the service + cache; full backend suite green
  (162/162).

Customer-app splash + register polish:
- Splash rewritten per figma S1: warm vertical gradient, two ImageFiltered
  radial orbs, 96×96 rounded-square logo tile, "HaloBestie" + "kamu gak
  harus ngerasain ini sendirian." Self-driving navigation via context.go
  after a 2.5s post-frame timer (native Android splash burns ~1-1.5s
  before Flutter paints — 1s timer yielded near-zero visible duration).
  Router early-returns null for isSplash so it never moves us off /splash
  on its own.
- 3-page onboarding carousel removed: user clarified the new splash
  REPLACES that carousel. Dropped /onboarding route, OnboardingScreen,
  onboardingDoneProvider + gating, dead splash_{1,2,3}.png + the
  splash_chat_hebat.png Flutter asset. Phase 4 /onboarding/* subroutes
  untouched; Android-native launch_background drawable left alone.
- Register screen (login-by-phone) polished: circular pink back button +
  72×72 logo badge (same brandLogoBg pink as splash, Transform.scale 1.4
  to fill the tile). Step-dots indicator removed.

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

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

@@ -0,0 +1,99 @@
+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`).
+class PaymentMethodEntry {
+  final String id;
+  final String paymentCode;
+  final String displayName;
+  final String? icon;
+
+  const PaymentMethodEntry({
+    required this.id,
+    required this.paymentCode,
+    required this.displayName,
+    this.icon,
+  });
+}
+
+/// One group in the payment-method catalog (server-side:
+/// `payment_method_groups`). Groups are already filtered + ordered by the
+/// backend — render verbatim.
+class PaymentMethodGroup {
+  final String id;
+  final String name;
+  final List<PaymentMethodEntry> methods;
+
+  const PaymentMethodGroup({
+    required this.id,
+    required this.name,
+    required this.methods,
+  });
+}
+
+class PaymentCatalog {
+  final List<PaymentMethodGroup> groups;
+  const PaymentCatalog(this.groups);
+
+  /// Whether this came from the hardcoded fallback (catalog endpoint failed).
+  /// UI uses this to optionally surface a "couldn't load all methods" hint.
+  final bool isFallback = false;
+}
+
+class _FallbackCatalog extends PaymentCatalog {
+  const _FallbackCatalog() : super(const [_kFallbackGroup]);
+  @override
+  bool get isFallback => true;
+}
+
+const _kFallbackGroup = PaymentMethodGroup(
+  id: 'fallback-paling-cepat',
+  name: 'Paling Cepat',
+  methods: [
+    PaymentMethodEntry(
+      id: 'fallback-qris',
+      paymentCode: 'QRIS',
+      displayName: 'QRIS',
+      icon: 'qris',
+    ),
+  ],
+);
+
+const PaymentCatalog kFallbackPaymentCatalog = _FallbackCatalog();
+
+/// App-facing catalog. Calls `GET /api/client/payment-methods`; on 5xx or
+/// network error returns [kFallbackPaymentCatalog] so checkout never
+/// hard-fails. See `requirement/phase5-payment-catalog-plan.md` §5.
+final paymentCatalogProvider = FutureProvider<PaymentCatalog>((ref) async {
+  final api = ref.read(apiClientProvider);
+  try {
+    final res = await api.get('/api/client/payment-methods');
+    final data = res['data'] as Map<String, dynamic>?;
+    final raw = data?['groups'] as List<dynamic>? ?? const [];
+    final groups = raw.map((g) {
+      final gm = g as Map<String, dynamic>;
+      final methods = (gm['methods'] as List<dynamic>? ?? const []).map((m) {
+        final mm = m as Map<String, dynamic>;
+        return PaymentMethodEntry(
+          id: mm['id'] as String,
+          paymentCode: mm['payment_code'] as String,
+          displayName: mm['display_name'] as String,
+          icon: mm['icon'] as String?,
+        );
+      }).toList(growable: false);
+      return PaymentMethodGroup(
+        id: gm['id'] as String,
+        name: gm['name'] as String,
+        methods: methods,
+      );
+    }).toList(growable: false);
+    // Defensive empty-catalog guard: if every group ended up empty after
+    // parsing, fall back so the user always sees at least QRIS.
+    if (groups.isEmpty || groups.every((g) => g.methods.isEmpty)) {
+      return kFallbackPaymentCatalog;
+    }
+    return PaymentCatalog(groups);
+  } catch (_) {
+    return kFallbackPaymentCatalog;
+  }
+});