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/widgets/pricing_bottom_sheet.dart

@@ -21,21 +21,42 @@ class PricingBottomSheet extends ConsumerStatefulWidget {
   /// Required — the in-progress chat session id this extension targets.
   final String extensionSessionId;
 
-  const PricingBottomSheet({super.key, required this.extensionSessionId});
+  /// Optional — fired when the customer chooses the "cukup, akhiri sesi"
+  /// ghost CTA. The sheet pops itself before invoking the callback so the
+  /// downstream confirm-end popup chain can stack on a clean route.
+  final VoidCallback? onEndSession;
+
+  const PricingBottomSheet({
+    super.key,
+    required this.extensionSessionId,
+    this.onEndSession,
+  });
 
   /// Show for session extension (from chat screen).
-  static Future<void> showForExtension(BuildContext context, {required String sessionId}) {
+  static Future<void> showForExtension(
+    BuildContext context, {
+    required String sessionId,
+    VoidCallback? onEndSession,
+  }) {
     return showModalBottomSheet(
       context: context,
       isScrollControlled: true,
       backgroundColor: HaloTokens.surface,
+      // Material 3 auto-injects a drag-handle widget above the sheet when
+      // the theme has one configured. We render our own pill inside
+      // `_Body` to control its exact tint/size — explicitly disable the
+      // auto one so the user doesn't see two stacked horizontal lines.
+      showDragHandle: false,
       shape: const RoundedRectangleBorder(
         borderRadius: BorderRadius.only(
           topLeft: Radius.circular(24),
           topRight: Radius.circular(24),
         ),
       ),
-      builder: (_) => PricingBottomSheet(extensionSessionId: sessionId),
+      builder: (_) => PricingBottomSheet(
+        extensionSessionId: sessionId,
+        onEndSession: onEndSession,
+      ),
     );
   }
 
@@ -72,6 +93,11 @@ class _PricingBottomSheetState extends ConsumerState<PricingBottomSheet> {
         );
   }
 
+  void _onEndSession() {
+    Navigator.of(context).pop();
+    widget.onEndSession?.call();
+  }
+
   @override
   Widget build(BuildContext context) {
     final pricingAsync = ref.watch(chatPricingProvider);
@@ -105,6 +131,7 @@ class _PricingBottomSheetState extends ConsumerState<PricingBottomSheet> {
               }),
               onTierTap: _onTierTap,
               onConfirm: _onConfirm,
+              onEndSession: widget.onEndSession != null ? _onEndSession : null,
             ),
           ),
         );
@@ -122,6 +149,7 @@ class _Body extends StatelessWidget {
   final ValueChanged<PaymentMode> onModeChanged;
   final ValueChanged<PriceTier> onTierTap;
   final ValueChanged<PriceTier> onConfirm;
+  final VoidCallback? onEndSession;
 
   const _Body({
     required this.pricing,
@@ -132,6 +160,7 @@ class _Body extends StatelessWidget {
     required this.onModeChanged,
     required this.onTierTap,
     required this.onConfirm,
+    required this.onEndSession,
   });
 
   @override
@@ -206,21 +235,35 @@ class _Body extends StatelessWidget {
                   },
                 ),
         ),
-        Container(
+        Padding(
+          // No top border here — the drag handle is the only top "divider"
+          // the figma shows. A second border above the action bar reads as a
+          // duplicate line stacked under the list separator visuals.
           padding: const EdgeInsets.fromLTRB(
             HaloSpacing.s24,
-            HaloSpacing.s8,
-            HaloSpacing.s24,
+            HaloSpacing.s12,
             HaloSpacing.s24,
+            HaloSpacing.s16,
           ),
-          decoration: const BoxDecoration(
-            border: Border(top: BorderSide(color: HaloTokens.border)),
-          ),
-          child: HaloButton(
-            label: ctaLabel,
-            size: HaloButtonSize.lg,
-            fullWidth: true,
-            onPressed: hasSelection ? () => onConfirm(selectedTier) : null,
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              HaloButton(
+                label: ctaLabel,
+                size: HaloButtonSize.lg,
+                fullWidth: true,
+                onPressed: hasSelection ? () => onConfirm(selectedTier) : null,
+              ),
+              if (onEndSession != null) ...[
+                const SizedBox(height: HaloSpacing.s8),
+                HaloButton(
+                  label: 'cukup, akhiri sesi',
+                  variant: HaloButtonVariant.ghost,
+                  fullWidth: true,
+                  onPressed: onEndSession,
+                ),
+              ],
+            ],
           ),
         ),
       ],