feat(chat): improve auto-scroll behavior during message generation

lib/features/chat/views/chat_page.dart

@@ -70,6 +70,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
   bool _autoScrollCallbackScheduled = false;
   bool _pendingConversationScrollReset = false;
   bool _suppressKeepPinnedOnce = false; // skip keep-pinned bottom after reset
+  bool _userPausedAutoScroll = false; // user scrolled away during generation
   String? _cachedGreetingName;
   bool _greetingReady = false;
 
@@ -132,6 +133,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
 
     _shouldAutoScrollToBottom = true;
     _pendingConversationScrollReset = false;
+    _userPausedAutoScroll = false;
     _scheduleAutoScrollToBottom();
   }
 
@@ -444,6 +446,9 @@ class _ChatPageState extends ConsumerState<ChatPage> {
       // Clear attachments after successful send
       ref.read(attachedFilesProvider.notifier).clearAll();
 
+      // Reset auto-scroll pause when user sends a new message
+      _userPausedAutoScroll = false;
+
       // Scroll to bottom after enqueuing (only if user was near bottom)
       WidgetsBinding.instance.addPostFrameCallback((_) {
         // Only auto-scroll if user was already near the bottom (within 300 px)
@@ -890,6 +895,12 @@ class _ChatPageState extends ConsumerState<ChatPage> {
 
   void _scrollToBottom({bool smooth = true}) {
     if (!_scrollController.hasClients) return;
+    // Reset user pause when explicitly scrolling to bottom
+    if (_userPausedAutoScroll) {
+      setState(() {
+        _userPausedAutoScroll = false;
+      });
+    }
     final position = _scrollController.position;
     final maxScroll = position.maxScrollExtent;
     final target = maxScroll.isFinite ? maxScroll : 0.0;
@@ -1145,7 +1156,8 @@ class _ChatPageState extends ConsumerState<ChatPage> {
 
     if (_shouldAutoScrollToBottom) {
       _scheduleAutoScrollToBottom();
-    } else {
+    } else if (!_userPausedAutoScroll) {
+      // Only keep-pinned to bottom if user hasn't paused auto-scroll
       WidgetsBinding.instance.addPostFrameCallback((_) {
         if (!mounted) return;
         if (_suppressKeepPinnedOnce) {
@@ -1154,6 +1166,8 @@ class _ChatPageState extends ConsumerState<ChatPage> {
           _suppressKeepPinnedOnce = false;
           return;
         }
+        // Skip if user has paused auto-scroll (double-check in callback)
+        if (_userPausedAutoScroll) return;
         const double keepPinnedThreshold = 60.0;
         final distanceFromBottom = _distanceFromBottom();
         if (distanceFromBottom > 0 &&
@@ -1167,7 +1181,34 @@ class _ChatPageState extends ConsumerState<ChatPage> {
     final topPadding =
         MediaQuery.of(context).padding.top + kToolbarHeight + Spacing.md;
     final bottomPadding = Spacing.lg + _inputHeight;
-    return CustomScrollView(
+
+    // Check if any message is currently streaming
+    final isStreaming = messages.any((msg) => msg.isStreaming);
+
+    return NotificationListener<ScrollNotification>(
+      onNotification: (notification) {
+        // Detect user-initiated scroll (drag gesture)
+        if (notification is ScrollStartNotification &&
+            notification.dragDetails != null) {
+          // User started dragging - pause auto-scroll during generation
+          if (isStreaming && !_userPausedAutoScroll) {
+            setState(() {
+              _userPausedAutoScroll = true;
+            });
+          }
+        }
+        // Re-enable auto-scroll when user scrolls to bottom
+        if (notification is ScrollEndNotification) {
+          final distanceFromBottom = _distanceFromBottom();
+          if (distanceFromBottom <= 5 && _userPausedAutoScroll) {
+            setState(() {
+              _userPausedAutoScroll = false;
+            });
+          }
+        }
+        return false; // Allow notification to continue bubbling
+      },
+      child: CustomScrollView(
         key: const ValueKey('actual_messages'),
         controller: _scrollController,
         keyboardDismissBehavior: ScrollViewKeyboardDismissBehavior.onDrag,
@@ -1296,6 +1337,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
             ),
           ),
         ],
+      ),
     );
   }
 
@@ -1489,6 +1531,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
     );
     if (conversationId != _lastConversationId) {
       _lastConversationId = conversationId;
+      _userPausedAutoScroll = false; // Reset pause on conversation change
       if (conversationId == null) {
         _shouldAutoScrollToBottom = true;
         _pendingConversationScrollReset = false;
@@ -1531,6 +1574,10 @@ class _ChatPageState extends ConsumerState<ChatPage> {
     final canScroll =
         _scrollController.hasClients &&
         _scrollController.position.maxScrollExtent > 0;
+    // Check if any message is currently streaming (for scroll button indicator)
+    final isStreamingAnyMessage = ref
+        .watch(chatMessagesProvider)
+        .any((msg) => msg.isStreaming);
 
     // On keyboard open, if already near bottom, auto-scroll to bottom to keep input visible
     if (keyboardVisible && !_lastKeyboardVisible) {
@@ -2209,10 +2256,25 @@ class _ChatPageState extends ConsumerState<ChatPage> {
                                           child: IconButton(
                                             onPressed: _scrollToBottom,
                                             splashRadius: 24,
+                                            tooltip:
+                                                _userPausedAutoScroll &&
+                                                    isStreamingAnyMessage
+                                                ? 'Resume auto-scroll'
+                                                : 'Scroll to bottom',
                                             icon: Icon(
-                                              Platform.isIOS
+                                              // Show play icon when auto-scroll
-                                                  ? CupertinoIcons.arrow_down
+                                              // is paused during streaming
-                                                  : Icons.keyboard_arrow_down,
+                                              _userPausedAutoScroll &&
+                                                      isStreamingAnyMessage
+                                                  ? (Platform.isIOS
+                                                        ? CupertinoIcons
+                                                              .play_arrow_solid
+                                                        : Icons.play_arrow)
+                                                  : (Platform.isIOS
+                                                        ? CupertinoIcons
+                                                              .arrow_down
+                                                        : Icons
+                                                              .keyboard_arrow_down),
                                               size: IconSize.lg,
                                               color: context
                                                   .conduitTheme