Phase 5/6 polish: end-session flow, notif sound on API 33+, Xendit webview

Customer end-of-session (figma §6):
- PricingBottomSheet: ghost "cukup, akhiri sesi" CTA + dedup divider
- chat_screen._runEndSessionFlow chains ConfirmEndStep1 → ConfirmEndStep2
  → ClosingMessageSheet (or "lewati saja" → close + /home). The four
  popup/sheet widgets already existed; this commit just wires them
- showModalBottomSheet: showDragHandle=false to suppress the Material 3
  auto-injected handle that was stacking with our own pill

Notification sound on API 33+:
- Bump channel halobestie_chat_v1 → halobestie_chat_v2, created from
  native Kotlin in MainActivity.kt with AudioAttributes contentType
  CONTENT_TYPE_SONIFICATION. flutter_local_notifications' default of
  CONTENT_TYPE_UNKNOWN was causing Android 13 to silently drop audio
  focus while the notification still posted (isNoisy=true). Both apps
- Backend FCM payload channelId updated to v2
- AndroidManifest meta-data: default_notification_icon + color → brand
  silhouette tinted pink instead of generic Android bell. Both apps

Customer pairing reliability:
- pairing_notifier: applyPairedFromPush({sessionId, mitraName}) unsticks
  searching screen when WS push failed and FCM/active-session-poll is
  the first signal. Idempotent across PairingSearchingData,
  PairingTargetedWaitingData, PairingErrorData (covers ALREADY_ACTIVE)
- notification_service: dispatches every FCM data payload to an
  onDataMessage callback (foreground + tap + cold-start). main.dart
  wires that to applyPairedFromPush on type=='paired'. Foreground
  'paired' no longer renders a local banner — screen self-advances
- main.dart activeSession listener also calls applyPairedFromPush when
  a session appears server-side while pairing is in a waiting state.
  Covers stale ALREADY_ACTIVE recovery without a full page refresh

Auth refresh token race:
- auth_notifier._refreshFromStorage shares a single in-flight Future
  across all callers (Auth.build + 401-retry path). Backend rotates
  refresh tokens, so concurrent callers using the same stored token
  would race → loser 401s → catch wipes flutter_secure_storage → user
  appears logged out after kill+reopen

Polish:
- method_pick_screen: resizeToAvoidBottomInset=false — prevents the
  one-frame overflow when entering with the previous screen's keyboard
  still animating out
- bestie_history: BestieHistoryItem now carries `status` (backend
  already returns it). Removed _rawHistoryProvider that fetched the
  same endpoint just to read status; the two providers could go out
  of sync mid-rebuild and throw RangeError(length) on indexing

Xendit Stage 8 (carried from WIP):
- xendit_checkout_screen: embedded webview hosting Xendit's invoice
  page (intercepts halobestie:// deeplink + return-page URLs for
  deterministic pop)
- waiting_payment_screen: auto-pushes the webview when the backend
  payload includes xendit_invoice_url; spinner card + "Buka ulang
  halaman pembayaran" CTA for the QR-fallback path
- pubspec: webview_flutter ^4.13.0

Maestro infra:
- subflows/onboarding_returning_user: drop the "Mulai" carousel wait
  (splash auto-advances since 2026-05-26); tap phone-field hint
  instead of point; drop hideKeyboard (sends BACK → /home when the
  IME isn't actually up)
- New flow ts-customer-06-01-end_session_via_timeup_sheet: drives
  the full path to the chat-expired banner. Last step blocked by a
  Maestro+Flutter gesture quirk on the perpanjang ElevatedButton
  (raw `adb input tap` works at the same coords). Documented in
  memory; deeplink fixture or manual verify recommended
- ChatExpiredBanner button wrapped with Semantics(identifier:
  'chat_extend_button', button: true, onTap: …) — good hygiene for
  future tests even though it doesn't fix the dadb tap issue

.dev/: tracked wsl_emulator_bridge.ps1 + wsl_tcp_relay.py for
Maestro-on-WSL setup (Windows-side netsh portproxy + WSL-side
loopback relays). Both referenced from existing CLAUDE.md notes.

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

client_app/lib/features/chat/screens/chat_screen.dart

@@ -10,6 +10,9 @@ import '../../../core/theme/halo_tokens.dart';
 import '../../../core/theme/widgets/halo_snackbar.dart';
 import '../widgets/bestie_unavailable_dialog.dart';
 import '../widgets/chat_expired_banner.dart';
+import '../widgets/closing_message_sheet.dart';
+import '../widgets/confirm_end_step1.dart';
+import '../widgets/confirm_end_step2.dart';
 import '../widgets/pricing_bottom_sheet.dart';
 
 /// S10 Chat Room — strict Figma implementation (Phase 4, 2026-05-12).
@@ -509,7 +512,14 @@ class _TimerBanner extends ConsumerWidget {
       return _BannerKind.none;
     }));
     void onExtend() {
-      PricingBottomSheet.showForExtension(context, sessionId: sessionId);
+      PricingBottomSheet.showForExtension(
+        context,
+        sessionId: sessionId,
+        // Figma 28→29→30→31: time-up sheet → confirm popup 1 → confirm popup
+        // 2 → closing-message sheet (or skip → home). The sheet pops itself
+        // before this fires, so the first dialog stacks on the chat route.
+        onEndSession: () => _runEndSessionFlow(context, ref, sessionId),
+      );
     }
     switch (kind) {
       case _BannerKind.lowTime:
@@ -522,6 +532,44 @@ class _TimerBanner extends ConsumerWidget {
   }
 }
 
+// Orchestrates the two-step confirm popup chain that follows the time-up
+// sheet's "cukup, akhiri sesi" CTA. ConfirmEndStep1/2 already pop themselves
+// before invoking the action callback (see HaloPopup), so we can chain
+// without manual Navigator.pop calls. The skip path closes the session via
+// the closure notifier and routes home; the "tulis pesan" path delegates to
+// the ClosingMessageSheet which calls closeSession itself in its onCompleted.
+Future<void> _runEndSessionFlow(
+  BuildContext context,
+  WidgetRef ref,
+  String sessionId,
+) async {
+  await ConfirmEndStep1.show(
+    context,
+    onConfirm: () async {
+      if (!context.mounted) return;
+      await ConfirmEndStep2.show(
+        context,
+        onWriteMessage: () {
+          if (!context.mounted) return;
+          ClosingMessageSheet.show(
+            context,
+            sessionId: sessionId,
+            onCompleted: () {
+              if (context.mounted) context.go('/home');
+            },
+          );
+        },
+        onSkip: () async {
+          await ref
+              .read(sessionClosureProvider.notifier)
+              .closeSession(sessionId);
+          if (context.mounted) context.go('/home');
+        },
+      );
+    },
+  );
+}
+
 // ─── Header (back · orb · name+status · timer pill) + progress bar ──────────
 
 class _ChatHeader extends ConsumerStatefulWidget {