fix(home): 修复按住说话功能，移除旧麦克风逻辑

apps/lib/features/home/ui/screens/home_screen.dart

@@ -792,10 +792,6 @@ class _HomeScreenState extends State<HomeScreen>
         borderRadius: BorderRadius.circular(_inputRadius),
         border: Border.all(color: AppColors.slate300),
       ),
-      child: Row(
-        crossAxisAlignment: CrossAxisAlignment.center,
-        children: [
-          Expanded(
       child: _isRecording
           ? _buildListeningIndicator()
           : _isTranscribing
@@ -818,28 +814,21 @@ class _HomeScreenState extends State<HomeScreen>
               ),
               onSubmitted: (_) => _sendMessage(context),
             ),
-          ),
-          const SizedBox(width: 8),
-          _buildInputActionIcon(state),
-        ],
-      ),
     );
   }
 
-  Widget _buildInputActionIcon(ChatState state) {
+  Widget _buildRightActionButton(ChatState state) {
     final isWaitingAgent =
         state.isWaitingFirstToken || state.isStreaming || state.isCancelling;
     return GestureDetector(
       key: _inputActionButtonKey,
       onTap: _isTranscribing
           ? null
-          : _isRecording
-          ? () => _stopRecording(autoSendAfterTranscribe: true)
           : isWaitingAgent
           ? () => _onStopGenerating(context)
           : _hasMessage
           ? () => _sendMessage(context)
-          : _startRecording,
+          : _toggleHoldToSpeakMode,
       child: _isTranscribing
           ? const SizedBox(
               width: _transcribingSpinnerSize,
@@ -853,43 +842,19 @@ class _HomeScreenState extends State<HomeScreen>
               key: _inputActionIconKey,
               isWaitingAgent
                   ? LucideIcons.square
-                  : _isRecording || _hasMessage
+                  : _hasMessage
                   ? LucideIcons.send
-                  : LucideIcons.mic,
+                  : _isHoldToSpeakMode
+                  ? LucideIcons.keyboard
+                  : LucideIcons.activity,
               size: _iconSize,
-              color: isWaitingAgent || _isRecording || _hasMessage
+              color: isWaitingAgent || _hasMessage
                   ? AppColors.blue600
                   : AppColors.slate500,
             ),
     );
   }
 
-  Widget _buildRightActionButton(ChatState state) {
-    return GestureDetector(
-      key: _inputActionButtonKey,
-      onTap: _isTranscribing
-          ? null
-          : _isHoldToSpeakMode
-          ? _toggleHoldToSpeakMode
-          : _startRecording,
-      child: _isTranscribing
-          ? const SizedBox(
-              width: _transcribingSpinnerSize,
-              height: _transcribingSpinnerSize,
-              child: CircularProgressIndicator(
-                strokeWidth: _transcribingStrokeWidth,
-                color: AppColors.blue600,
-              ),
-            )
-          : Icon(
-              key: _inputActionIconKey,
-              _isHoldToSpeakMode ? LucideIcons.keyboard : LucideIcons.activity,
-              size: _iconSize,
-              color: AppColors.slate500,
-            ),
-    );
-  }
-
   Widget _buildHoldToSpeakHint() {
     return Column(
       children: [