Phase 3: closing-overlay fix + goodbye-composer dedupe

Customer chat refreshSessionStatus now clears sessionExpired carryover so the
goodbye composer renders correctly when re-opening a closing session from
history. Backend /api/shared/chat/:id/info returns goodbye_submitted_by_me;
both apps suppress the composer for the side that has already submitted and
render an awaiting-banner view instead.

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

mitra_app/lib/core/chat/mitra_chat_notifier.dart

@@ -29,6 +29,7 @@ class MitraChatConnectedData extends MitraChatData {
   final int? remainingSeconds;
   final bool sessionExpired;
   final bool sessionClosing;
+  final bool goodbyeSubmitted;
   final Map<String, dynamic>? extensionRequest;
   final TopicSensitivity topicSensitivity;
 
@@ -38,6 +39,7 @@ class MitraChatConnectedData extends MitraChatData {
     this.remainingSeconds,
     this.sessionExpired = false,
     this.sessionClosing = false,
+    this.goodbyeSubmitted = false,
     this.extensionRequest,
     this.topicSensitivity = TopicSensitivity.regular,
   });
@@ -48,6 +50,7 @@ class MitraChatConnectedData extends MitraChatData {
     int? remainingSeconds,
     bool? sessionExpired,
     bool? sessionClosing,
+    bool? goodbyeSubmitted,
     Map<String, dynamic>? extensionRequest,
     bool clearExtensionRequest = false,
     TopicSensitivity? topicSensitivity,
@@ -58,6 +61,7 @@ class MitraChatConnectedData extends MitraChatData {
       remainingSeconds: remainingSeconds ?? this.remainingSeconds,
       sessionExpired: sessionExpired ?? this.sessionExpired,
       sessionClosing: sessionClosing ?? this.sessionClosing,
+      goodbyeSubmitted: goodbyeSubmitted ?? this.goodbyeSubmitted,
       extensionRequest: clearExtensionRequest ? null : (extensionRequest ?? this.extensionRequest),
       topicSensitivity: topicSensitivity ?? this.topicSensitivity,
     );
@@ -124,6 +128,7 @@ class MitraChat extends _$MitraChat {
       }
 
       final isClosing = sessionStatus == SessionStatus.closing;
+      final goodbyeSubmittedByMe = sessionData?['goodbye_submitted_by_me'] as bool? ?? false;
       final sessionTopic = TopicSensitivity.fromString(sessionData?['topic_sensitivity'] as String?);
 
       final response = await _apiClient.get('/api/shared/chat/$sessionId/messages');
@@ -162,7 +167,12 @@ class MitraChat extends _$MitraChat {
         'session_id': sessionId,
       }));
 
-      state = MitraChatConnectedData(messages: messages, sessionClosing: isClosing, topicSensitivity: sessionTopic);
+      state = MitraChatConnectedData(
+        messages: messages,
+        sessionClosing: isClosing,
+        goodbyeSubmitted: goodbyeSubmittedByMe,
+        topicSensitivity: sessionTopic,
+      );
     } catch (e) {
       state = const MitraChatErrorData('Gagal terhubung ke chat.');
     }

mitra_app/lib/features/chat/screens/mitra_chat_screen.dart

@@ -268,11 +268,19 @@ class _MitraChatScreenState extends ConsumerState<MitraChatScreen> {
       return _buildExtensionView(state.extensionRequest!, extState);
     }
 
-    // Goodbye view
-    if (state.sessionClosing || extState is ExtensionShowGoodbyeData || extState is ExtensionSubmittingData) {
+    // Goodbye view — suppress if mitra has already submitted their goodbye;
+    // session can stay in `closing` while waiting for the customer to submit
+    // theirs or for the 5-min grace timer to auto-complete.
+    final showGoodbye = !state.goodbyeSubmitted &&
+        (state.sessionClosing || extState is ExtensionShowGoodbyeData || extState is ExtensionSubmittingData);
+    if (showGoodbye) {
       return _buildGoodbyeView(extState);
     }
 
+    if (state.sessionClosing && state.goodbyeSubmitted) {
+      return _buildAwaitingCustomerGoodbyeView(state);
+    }
+
     final bgTint = SensitivityTheme.of(state.topicSensitivity).bgTint;
 
     return Stack(
@@ -544,4 +552,55 @@ class _MitraChatScreenState extends ConsumerState<MitraChatScreen> {
         ),
     );
   }
+
+  Widget _buildAwaitingCustomerGoodbyeView(MitraChatConnectedData state) {
+    final bgTint = SensitivityTheme.of(state.topicSensitivity).bgTint;
+    return Stack(
+      children: [
+        Positioned.fill(
+          child: Container(
+            color: bgTint,
+            child: Image.asset(
+              'assets/images/chat_pattern.png',
+              repeat: ImageRepeat.repeat,
+              fit: BoxFit.none,
+            ),
+          ),
+        ),
+        Column(
+          children: [
+            Container(
+              width: double.infinity,
+              color: Colors.amber.shade100,
+              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
+              child: Row(
+                children: [
+                  Icon(Icons.hourglass_top, color: Colors.amber.shade900, size: 20),
+                  const SizedBox(width: 8),
+                  Expanded(
+                    child: Text(
+                      'Pesan penutupmu sudah terkirim. Menunggu user...',
+                      style: TextStyle(color: Colors.amber.shade900, fontWeight: FontWeight.w600),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+            Expanded(
+              child: ListView.builder(
+                controller: _scrollController,
+                padding: const EdgeInsets.all(16),
+                itemCount: state.messages.length,
+                itemBuilder: (context, index) {
+                  final msg = state.messages[index];
+                  final isMe = msg.senderType == UserType.mitra;
+                  return _buildMessageBubble(msg, isMe);
+                },
+              ),
+            ),
+          ],
+        ),
+      ],
+    );
+  }
 }