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/assets/payment_icons/NOTICE_IDN_FINLOGOS.txt

@@ -0,0 +1,31 @@
+Logo Assets License — Creative Commons Attribution-NonCommercial 4.0 International
+(CC BY-NC 4.0)
+
+This license applies to all SVG logo assets in `icons/` and `dist/icons/`.
+
+Copyright (c) 2026 Hafidz Noor Fauzi (collection/curation only).
+
+The underlying logo marks remain the property of their respective trademark
+holders. See NOTICE for details on trademark ownership and disclaimers.
+
+You are free to:
+  - Share — copy and redistribute the material in any medium or format.
+  - Adapt — remix, transform, and build upon the material.
+
+Under the following terms:
+  - Attribution — You must give appropriate credit, provide a link to this
+    license, and indicate if changes were made. You may do so in any
+    reasonable manner, but not in any way that suggests the licensor
+    endorses you or your use.
+  - NonCommercial — You may not use the material for commercial purposes.
+
+No additional restrictions — You may not apply legal terms or technological
+measures that legally restrict others from doing anything the license permits.
+
+Full license text:
+  https://creativecommons.org/licenses/by-nc/4.0/legalcode
+
+Human-readable summary:
+  https://creativecommons.org/licenses/by-nc/4.0/
+
+THE LOGO ASSETS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.