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/auth/screens/register_screen.dart

@@ -11,7 +11,6 @@ import '../../../core/theme/widgets/widgets.dart';
 /// S3a — WhatsApp input screen.
 ///
 /// Visual contract is `Figma/screens/onboarding.jsx::S3Phone`:
-///   - HaloStepDots at the top (step 3 of 4: S2 Nama → S5 ESP → S5b USP → S3a)
 ///   - Personalised display-title `"nomor wa-mu, {name}?"`
 ///   - +62 prefix as static chip; user types only the trailing digits
 ///   - Privacy reassurance card
@@ -137,9 +136,21 @@ class _RegisterScreenState extends ConsumerState<RegisterScreen> {
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.stretch,
             children: [
-              const Padding(
-                padding: EdgeInsets.only(top: 8, bottom: 8),
-                child: HaloStepDots(total: 4, current: 3),
+              Padding(
+                padding: const EdgeInsets.only(top: 4, bottom: 4),
+                child: Row(
+                  children: [
+                    _CircleBackButton(
+                      onTap: () {
+                        if (Navigator.of(context).canPop()) {
+                          Navigator.of(context).pop();
+                        } else {
+                          context.go('/home');
+                        }
+                      },
+                    ),
+                  ],
+                ),
               ),
               Expanded(
                 child: LayoutBuilder(
@@ -152,6 +163,8 @@ class _RegisterScreenState extends ConsumerState<RegisterScreen> {
                           mainAxisAlignment: MainAxisAlignment.center,
                           crossAxisAlignment: CrossAxisAlignment.stretch,
                           children: [
+                            const Center(child: _LogoBadge()),
+                            const SizedBox(height: 18),
                             Text(
                               'nomor wa-mu, $shownName?',
                               style: const TextStyle(
@@ -312,6 +325,58 @@ class _PhoneRow extends StatelessWidget {
   }
 }
 
+class _CircleBackButton extends StatelessWidget {
+  final VoidCallback onTap;
+  const _CircleBackButton({required this.onTap});
+
+  @override
+  Widget build(BuildContext context) {
+    return Material(
+      color: HaloTokens.brand,
+      shape: const CircleBorder(),
+      elevation: 2,
+      shadowColor: const Color(0x1F000000),
+      child: InkWell(
+        customBorder: const CircleBorder(),
+        onTap: onTap,
+        child: const SizedBox(
+          width: 40,
+          height: 40,
+          child: Icon(Icons.arrow_back, color: Colors.white, size: 20),
+        ),
+      ),
+    );
+  }
+}
+
+class _LogoBadge extends StatelessWidget {
+  const _LogoBadge();
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: 72,
+      height: 72,
+      decoration: BoxDecoration(
+        color: HaloTokens.brandLogoBg,
+        borderRadius: BorderRadius.circular(20),
+        boxShadow: const [
+          BoxShadow(
+            color: Color(0x47FF69A0),
+            blurRadius: 18,
+            offset: Offset(0, 6),
+          ),
+        ],
+      ),
+      clipBehavior: Clip.antiAlias,
+      child: Transform.scale(
+        scale: 1.4,
+        child: Image.asset('assets/icons/logo.png', fit: BoxFit.cover),
+      ),
+    );
+  }
+}
+
 class _PrivacyCard extends StatelessWidget {
   const _PrivacyCard();