Phase 4 Stage 8: returning-user shell + Tanya Admin sheet

Bestie Choice Sheet on home Mulai Curhat CTA. When the user has at
least one prior session (bestieHistoryHasItemsProvider hits the chat-
sessions history endpoint), the CTA opens a HaloBottomSheet with two
cards: 'bestie yang udah kenal' -> /chat/history, 'bestie baru' ->
/payment/entry. Empty history -> direct to /payment/entry.

Bestie history list visual upgrade: HaloOrb (mitraId seed) + name +
last-session date + topic pills + sessions count + ONLINE pill.
Backend getCustomerHistory now returns topics, mitra_is_online,
sessions_count in a single payload (no per-row presence round-trip).

BestieOfflinePopup with two variants (returning | new_) replacing the
legacy BestieUnavailableDialog. tanya admin ghost CTA on both variants
opens the new TanyaAdminSheet. Stage 5's targeted-wait declined stub
+ Stage 7's chat-screen 409 stub + searching-screen call site all
migrated to the real component.

TanyaAdminSheet: HaloBottomSheet with WA + Telegram buttons, deeplinks
fetched via supportHandlesProvider (CC-config-driven). url_launcher
added to client_app; ios LSApplicationQueriesSchemes covers
https/http/whatsapp/tg.

Stage 2's OTP-blocked popup hubungi admin SnackBar stub also migrated
to TanyaAdminSheet.

Dev-only POST /internal/_test/seed-history-session lets Maestro 08
flow seed a history row before exercising the choice sheet.

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

client_app/lib/features/home/home_screen.dart

@@ -6,6 +6,8 @@ import '../../core/availability/mitra_availability_notifier.dart';
 import '../../core/chat/active_session_notifier.dart';
 import '../../core/notifications/notif_permission.dart';
 import '../../core/theme/halo_tokens.dart';
+import 'providers/bestie_history_provider.dart';
+import 'widgets/bestie_choice_sheet.dart';
 
 /// Session-only dismiss flag for the "notif denied" banner. Resets on cold
 /// restart by design — `StateProvider` lives in memory only.
@@ -58,16 +60,27 @@ class _HomeScreenState extends ConsumerState<HomeScreen> with WidgetsBindingObse
     }
   }
 
-  void _onStartChatPressed(BuildContext context) {
+  Future<void> _onStartChatPressed(BuildContext context) async {
     // Phase 4 Stage 2 removes the home-screen topic sensitivity prompt; the
     // ESP picks collected during onboarding feed the same column server-side
     // (info-only — no longer drives matching). Mitras still flip
     // `topic_sensitivity` mid-session via the AppBar toggle.
     //
-    // Phase 4 Stage 3: enter the new multi-screen payment shell. The entry
-    // route picks discount-paywall vs. method-pick based on first-session
-    // eligibility. The legacy `/payment` route is preserved for the
-    // chat-history "Curhat lagi" path until Stage 5 migrates it.
+    // Phase 4 Stage 8: returning users get the bestie-choice sheet first; new
+    // users skip straight to the multi-screen payment shell. We fetch the
+    // history-has-items flag on-tap so a stale cache from logout/login doesn't
+    // mis-route. On error (e.g. offline), fall back to the new-user path.
+    bool hasHistory;
+    try {
+      hasHistory = await ref.read(bestieHistoryHasItemsProvider.future);
+    } catch (_) {
+      hasHistory = false;
+    }
+    if (!context.mounted) return;
+    if (hasHistory) {
+      await BestieChoiceSheet.show(context);
+      return;
+    }
     context.push('/payment/entry');
   }