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/lib/core/chat/chat_opening_provider.dart

@@ -8,27 +8,97 @@ class PriceTier {
   final int durationMinutes;
   final int price;
   final String label;
+  final String? id;
+  final String? tag;
 
-  PriceTier({required this.durationMinutes, required this.price, required this.label});
+  const PriceTier({
+    required this.durationMinutes,
+    required this.price,
+    required this.label,
+    this.id,
+    this.tag,
+  });
 
+  /// Phase 4 shape: `{ id, minutes, price_idr, tag }` — used by the new
+  /// chat/call tier groups. Falls back to the legacy free-trial-pricing shape
+  /// (`{ duration_minutes, price, label }`) for back-compat with the Phase 3
+  /// `/api/client/chat/pricing` payload still consumed by the legacy payment
+  /// screen + bottom sheet.
   factory PriceTier.fromJson(Map<String, dynamic> json) {
+    final minutes = (json['minutes'] ?? json['duration_minutes']) as int;
+    final price = (json['price_idr'] ?? json['price']) as int;
+    final label = (json['label'] as String?) ?? '$minutes Menit';
     return PriceTier(
-      durationMinutes: json['duration_minutes'] as int,
-      price: json['price'] as int,
-      label: json['label'] as String,
+      durationMinutes: minutes,
+      price: price,
+      label: label,
+      id: (json['id'] as String?) ?? minutes.toString(),
+      tag: json['tag'] as String?,
+    );
+  }
+}
+
+/// First-session discount block. Mirrors backend
+/// `pricing.first_session_discount`. Server-authoritative — the client only
+/// reads this; the actual discount price is re-validated on the backend when
+/// the payment session is created.
+class FirstSessionDiscount {
+  final bool eligible;
+  final int actualPriceIDR;
+  final int gimmickPriceIDR;
+  final int durationMinutes;
+  final List<String> modes;
+
+  const FirstSessionDiscount({
+    required this.eligible,
+    required this.actualPriceIDR,
+    required this.gimmickPriceIDR,
+    required this.durationMinutes,
+    required this.modes,
+  });
+
+  factory FirstSessionDiscount.fromJson(Map<String, dynamic> json) {
+    final modesRaw = json['modes'];
+    final modes = modesRaw is List
+        ? modesRaw.map((e) => e.toString()).toList()
+        : const <String>['chat'];
+    return FirstSessionDiscount(
+      eligible: json['eligible'] as bool? ?? false,
+      actualPriceIDR: json['actual_price_idr'] as int? ?? 0,
+      gimmickPriceIDR: json['gimmick_price_idr'] as int? ?? 0,
+      durationMinutes: json['duration_minutes'] as int? ?? 0,
+      modes: modes,
     );
   }
 }
 
 class PricingData {
+  /// Legacy single-list tiers. Populated from `data.tiers` when the response
+  /// uses the Phase 3 shape; populated from `data.chat.tiers` when the
+  /// Phase 4 shape is returned (so existing callers keep working).
   final List<PriceTier> tiers;
   final bool freeTrialEligible;
   final int freeTrialDurationMinutes;
 
+  /// Phase 4 chat-mode tiers (`pricing.chat.tiers`). Empty when the backend
+  /// still returns the Phase 3 shape.
+  final List<PriceTier> chatTiers;
+
+  /// Phase 4 call-mode tiers (`pricing.call.tiers`). Empty when the backend
+  /// still returns the Phase 3 shape.
+  final List<PriceTier> callTiers;
+
+  /// Phase 4 first-session discount block. Null when the backend still
+  /// returns the Phase 3 shape.
+  final FirstSessionDiscount? firstSessionDiscount;
+
   const PricingData({
     required this.tiers,
     required this.freeTrialEligible,
     this.freeTrialDurationMinutes = 5,
+    this.chatTiers = const [],
+    this.callTiers = const [],
+    this.firstSessionDiscount,
   });
 }
 
@@ -37,9 +107,35 @@ Future<PricingData> chatPricing(Ref ref) async {
   final apiClient = ref.read(apiClientProvider);
   final response = await apiClient.get('/api/client/chat/pricing');
   final data = response['data'] as Map<String, dynamic>;
+
+  // Phase 4 shape — `data.chat.tiers` + `data.call.tiers` + `first_session_discount`.
+  // Phase 3 shape — `data.tiers` + `data.free_trial`. Detect which we got and
+  // populate the model accordingly.
+  final hasPhase4Groups = data['chat'] is Map<String, dynamic>;
+
+  if (hasPhase4Groups) {
+    final chat = data['chat'] as Map<String, dynamic>;
+    final call = (data['call'] as Map<String, dynamic>?) ?? const {};
+    final chatTiers = (chat['tiers'] as List<dynamic>? ?? const [])
+        .map((t) => PriceTier.fromJson(t as Map<String, dynamic>))
+        .toList();
+    final callTiers = (call['tiers'] as List<dynamic>? ?? const [])
+        .map((t) => PriceTier.fromJson(t as Map<String, dynamic>))
+        .toList();
+    final discountJson = data['first_session_discount'] as Map<String, dynamic>?;
+    final discount = discountJson != null ? FirstSessionDiscount.fromJson(discountJson) : null;
+    return PricingData(
+      tiers: chatTiers,
+      freeTrialEligible: false,
+      chatTiers: chatTiers,
+      callTiers: callTiers,
+      firstSessionDiscount: discount,
+    );
+  }
+
   final tiersJson = data['tiers'] as List<dynamic>;
   final tiers = tiersJson.map((t) => PriceTier.fromJson(t as Map<String, dynamic>)).toList();
-  final freeTrial = data['free_trial'] as Map<String, dynamic>;
+  final freeTrial = (data['free_trial'] as Map<String, dynamic>?) ?? const {};
 
   return PricingData(
     tiers: tiers,

client_app/lib/core/chat/chat_opening_provider.g.dart

@@ -6,7 +6,7 @@ part of 'chat_opening_provider.dart';
 // RiverpodGenerator
 // **************************************************************************
 
-String _$chatPricingHash() => r'53ca829d46f7ba3b481e7a6b54482c62f9fe3ad0';
+String _$chatPricingHash() => r'6dfbdf77942a67d3da689849eda89fc1fa3e6e39';
 
 /// See also [chatPricing].
 @ProviderFor(chatPricing)