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/README.md

@@ -0,0 +1,79 @@
+# Payment method icons
+
+Bundled SVGs referenced by the payment catalog (`payment_methods.icon` slug
+in the backend). The customer app's `PaymentIcon` widget resolves
+`<slug>.svg` from this directory and falls back to `placeholder.svg` when the
+file isn't bundled — see `client_app/lib/features/payment/widgets/payment_icon.dart`.
+
+## Naming convention
+
+One SVG per slug, lower-case, hyphens not underscores. Currently bundled
+slugs (match the migrate.js seed):
+
+| Slug | Method | Source filename in `idn-finlogos/icons/` |
+|---|---|---|
+| `qris` | QRIS | `qris.svg` |
+| `ovo` | OVO | `ovo-new.svg` |
+| `dana` | DANA | `dana.svg` |
+| `shopeepay` | ShopeePay | `shopee-pay.svg` |
+| `gopay` | GoPay (seeded inactive) | `gopay.svg` |
+| `bca` | BCA Virtual Account | `bca.svg` |
+| `mandiri` | Mandiri Virtual Account | `mandiri.svg` |
+| `bni` | BNI Virtual Account | `bni.svg` |
+| `bri` | BRI Virtual Account | `bri.svg` |
+| `permata` | Permata Virtual Account | `permata.svg` |
+
+## Sourcing — idn-finlogos
+
+We pull individual SVGs from
+[github.com/hafidznoor/idn-finlogos](https://github.com/hafidznoor/idn-finlogos)
+rather than installing the Flutter package (`idn_finlogos` on pub.dev). The
+package bundles all 572 SVGs as Flutter assets — Flutter doesn't tree-shake
+assets, so adding the package ships ~4-6 MB of marks we never use. Manual
+copy keeps the APK lean: 10 marks ≈ 80 KB on-disk.
+
+See `NOTICE_IDN_FINLOGOS.txt` for the upstream licensing terms (MIT for build
+tooling, CC BY-NC 4.0 for the SVG assets, plus the project's note that
+individual brand marks require permission from each brand holder for
+commercial use).
+
+## Adding a new method
+
+1. **Catalog row** (control center → Payment Catalog):
+   - Add a method with `payment_code` set to the Xendit channel code
+     (uppercase, e.g. `LINKAJA`) and `icon` set to the desired slug
+     (lowercase, e.g. `linkaja`).
+   - Method renders immediately with the generic placeholder icon.
+2. **Branded SVG** (one-time, requires an app release):
+   ```sh
+   cd client_app/assets/payment_icons
+   curl -sS https://raw.githubusercontent.com/hafidznoor/idn-finlogos/main/icons/<source>.svg -o <slug>.svg
+   ```
+   (Browse the repo's `icons/` directory if the source filename isn't an
+   exact match — e.g. `ovo-new.svg` for the modern OVO mark.)
+3. **Append the slug** to `_kBundledSlugs` in
+   `client_app/lib/features/payment/widgets/payment_icon.dart` so the widget
+   stops falling back to the placeholder for that slug.
+4. **Cut a release.** Assets ship with the APK; new icons need a binary update.
+
+## Why the explicit `_kBundledSlugs` list?
+
+Flutter's asset system throws if a referenced asset is missing — there's no
+"file exists?" check at runtime without round-tripping the AssetManifest.
+Keeping the bundled-slugs list in code makes "what we ship" explicit and
+keeps the icon widget cheap.
+
+## When to migrate to the pub package
+
+The manual-copy approach beats `idn_finlogos` as long as we bundle fewer
+than ~50 icons (where the ~4-6 MB whole-library payload starts looking
+reasonable compared to per-file curl-and-commit overhead). If we cross that
+threshold, switch:
+
+```yaml
+dependencies:
+  idn_finlogos: ^2.3.0
+```
+
+…and delete this directory's per-icon SVGs (keep `placeholder.svg` + the
+slug allowlist).