Phase 4 Stage 3: payment shell (multi-screen flow)

Six new screens under /payment/* + a paymentDraftProvider holding
mode/durationId/durationMinutes/priceIDR/paymentId/isFirstSessionDiscount
across the flow. PaymentEntryScreen handles the routing decision
(eligible+enabled -> /payment/discount-paywall, else /payment/method-pick)
and clears the draft on fresh entry.

Screens:
- discount_paywall_screen: S6 first-session discount with struck-through
  gimmick price + actual price + 'mulai · Rp{actual}' CTA -> /payment/method
- method_pick_screen: chat vs call cards
- duration_pick_screen: tier list with chat|call mode toggle that resets
  the selection on swap
- payment_method_screen: QRIS-first list, posts to existing
  /api/client/payment-sessions with mode/duration/price/discount/method
- waiting_payment_screen: qr_flutter QR (encodes paymentId in mock mode),
  20-min countdown header, 3s polling for status, pauses on background
  via WidgetsBindingObserver
- payment_expired_screen: retry CTA -> /payment/method with draft retained

Status mapping: real payment_sessions.status uses 'confirmed'/'consumed'
for paid (not 'paid' as in plan) and 'expired'/'abandoned' as terminal.

home_screen 'Mulai Curhat' CTA now pushes /payment/entry.

Dev-only /internal/_test/force-expire-payment endpoint to drive Maestro
flow 04_payment_expired.yaml without waiting 20 minutes. Gated behind
NODE_ENV !== 'production'.

chat_opening_provider PricingData extended to carry Phase 4 chat/call
groups + firstSessionDiscount, back-compat with the Phase 3 shape.

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

client_app/.maestro/flows/04_payment_expired.yaml

@@ -0,0 +1,94 @@
+# Stage 3 acceptance: drive a payment session into the expired state and
+# verify the expired screen renders.
+#
+# Flow:
+#   home → tap CTA → /payment/entry → /payment/method-pick (or
+#   discount-paywall — both arrive at /payment/method) → /payment/method →
+#   tap bayar → /payment/waiting/:id → force-expire via dev endpoint →
+#   poller transitions to /payment/expired/:id.
+#
+# Pre-req:
+#   1. The customer is already onboarded + on /home (run flow 01 first, or
+#      launchApp with clearState=false on a state past onboarding).
+#   2. At least one mitra is ONLINE on the target backend (so the CTA is
+#      enabled). Use mitra_app or the manual seed.
+#   3. Backend reachable at BACKEND_INTERNAL_URL with NODE_ENV != 'production'
+#      (so the _test routes register).
+#
+# Run:
+#   maestro test client_app/.maestro/flows/04_payment_expired.yaml
+appId: ${APP_ID_ANDROID}
+env:
+  BACKEND_INTERNAL_URL: http://localhost:3001
+---
+- launchApp:
+    clearState: false
+- assertVisible: "Mulai Curhat"
+
+# Step 1: tap CTA — home routes to /payment/entry which decides the next leg
+# based on first-session-discount eligibility.
+- tapOn: "Mulai Curhat"
+
+# Step 2: regardless of which entry path was chosen, the customer ends up at
+# /payment/method-pick (non-eligible) or /payment/discount-paywall (eligible).
+# Both have a way forward to /payment/method. Wait for either landmark.
+- extendedWaitUntil:
+    visible:
+      text: "pilih cara curhat|sesi pertama|pilih durasi"
+    timeout: 10000
+
+# Step 3: pick chat (if on method-pick) and a tier (if on duration-pick),
+# or tap mulai (if on discount paywall). Each branch funnels into
+# /payment/method.
+- runFlow:
+    when:
+      visible:
+        text: "pilih cara curhat"
+    commands:
+      - tapOn: "chat"
+      - extendedWaitUntil:
+          visible:
+            text: "pilih durasi"
+          timeout: 5000
+      - tapOn:
+          text: "5 menit"
+          retryTapIfNoChange: true
+      - tapOn:
+          text: "bayar"
+          retryTapIfNoChange: true
+- runFlow:
+    when:
+      visible:
+        text: "sesi pertama"
+    commands:
+      - tapOn:
+          text: "mulai"
+          retryTapIfNoChange: true
+
+# Step 4: on the cara-bayar screen, QRIS is preselected. Tap pay.
+- extendedWaitUntil:
+    visible:
+      text: "cara bayar"
+    timeout: 10000
+- tapOn:
+    text: "bayar"
+    retryTapIfNoChange: true
+
+# Step 5: we should now be on the QR/waiting screen. The header shows the
+# countdown ("kedaluwarsa dalam"). Force-expire via the dev endpoint.
+- extendedWaitUntil:
+    visible:
+      text: "kedaluwarsa dalam"
+    timeout: 10000
+- runScript:
+    file: ../scripts/force_expire_latest_payment.js
+    env:
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+
+# Step 6: poller picks up `expired` within ~3s and routes to expired screen.
+- extendedWaitUntil:
+    visible:
+      text: "pembayaran kedaluwarsa"
+    timeout: 10000
+- assertVisible: "coba lagi"
+- assertVisible: "kembali ke home"