feat(chat): Improve keyboard shortcuts and accessibility in chat input

lib/features/chat/widgets/modern_chat_input.dart

@@ -1285,6 +1285,9 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
   }) {
     return GestureDetector(
       behavior: HitTestBehavior.opaque,
+      // Exclude from semantics so screen readers interact directly with the
+      // TextField, which provides its own accessibility via hintText.
+      excludeFromSemantics: true,
       onTap: () {
         if (!widget.enabled) return;
         // Explicit user intent to focus: re-enable autofocus and focus
@@ -1293,21 +1296,13 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
         } catch (_) {}
         _ensureFocusedIfEnabled();
       },
-      child: MergeSemantics(
-        child: Semantics(
-          label: AppLocalizations.of(context)!.messageInputLabel,
-          hint: AppLocalizations.of(context)!.messageInputHint,
       child: Shortcuts(
         shortcuts: () {
           final map = <LogicalKeySet, Intent>{
-                LogicalKeySet(
+            LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.enter):
-                  LogicalKeyboardKey.meta,
+                const _SendMessageIntent(),
-                  LogicalKeyboardKey.enter,
+            LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.enter):
-                ): const _SendMessageIntent(),
+                const _SendMessageIntent(),
-                LogicalKeySet(
-                  LogicalKeyboardKey.control,
-                  LogicalKeyboardKey.enter,
-                ): const _SendMessageIntent(),
           };
           if (sendOnEnter) {
             map[LogicalKeySet(LogicalKeyboardKey.enter)] =
@@ -1346,8 +1341,7 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
                 return null;
               },
             ),
-                _SelectNextPromptIntent:
+            _SelectNextPromptIntent: CallbackAction<_SelectNextPromptIntent>(
-                    CallbackAction<_SelectNextPromptIntent>(
               onInvoke: (intent) {
                 _movePromptSelection(1);
                 return null;
@@ -1384,10 +1378,15 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
               final FontWeight recordingWeight = _isRecording
                   ? FontWeight.w500
                   : FontWeight.w400;
-                  final TextStyle baseChatStyle =
+              final TextStyle baseChatStyle = AppTypography.chatMessageStyle;
-                      AppTypography.chatMessageStyle;
 
-                  return TextField(
+              // Wrap with Semantics to provide an accessible label for screen
+              // readers. We avoid MergeSemantics which caused double-
+              // announcements. The TextField provides its own text field
+              // semantics; this just adds the descriptive label.
+              return Semantics(
+                label: AppLocalizations.of(context)!.messageInputLabel,
+                child: TextField(
                   controller: _controller,
                   focusNode: _focusNode,
                   enabled: widget.enabled,
@@ -1431,8 +1430,7 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
                     alignLabelWithHint: true,
                   ),
                   // Enable pasting images and files from clipboard
-                    contentInsertionConfiguration:
+                  contentInsertionConfiguration: ContentInsertionConfiguration(
-                        ContentInsertionConfiguration(
                     allowedMimeTypes: ClipboardAttachmentService
                         .supportedImageMimeTypes
                         .toList(),
@@ -1447,13 +1445,12 @@ class _ModernChatInputState extends ConsumerState<ModernChatInput>
                     if (!widget.enabled) return;
                     _ensureFocusedIfEnabled();
                   },
+                ),
               );
             },
           ),
         ),
       ),
-        ),
-      ),
     );
   }