refactor(apps): 主题系统迁移至 ColorScheme + 扩展架构并支持 Dark Mode

apps/lib/features/home/presentation/widgets/home_composer_stack.dart

@@ -115,6 +115,8 @@ class HomeComposerStack extends StatelessWidget {
   }
 
   Widget _buildTextInputContent(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     if (isTranscribing) {
       return _buildTranscribingIndicator(context);
     }
@@ -126,10 +128,10 @@ class HomeComposerStack extends StatelessWidget {
           focusNode: messageFocusNode,
           minLines: 1,
           maxLines: 1,
-          style: const TextStyle(
+          style: TextStyle(
             fontSize: AppSpacing.lg,
             height: 1,
-            color: AppColors.slate900,
+            color: colorScheme.onSurface,
           ),
           textAlignVertical: TextAlignVertical.center,
           decoration: InputDecoration(
@@ -137,7 +139,7 @@ class HomeComposerStack extends StatelessWidget {
             hintStyle: TextStyle(
               fontSize: AppSpacing.lg,
               height: 1,
-              color: AppColors.slate400,
+              color: colorScheme.onSurfaceVariant,
             ),
             border: InputBorder.none,
             enabledBorder: InputBorder.none,
@@ -156,29 +158,31 @@ class HomeComposerStack extends StatelessWidget {
   }
 
   Widget _buildTranscribingIndicator(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     return Row(
       crossAxisAlignment: CrossAxisAlignment.center,
       children: [
         SizedBox(
           width: 18,
           height: 18,
-          child: const AppLoadingIndicator(
+          child: AppLoadingIndicator(
             variant: AppLoadingVariant.inline,
             size: 18,
             strokeWidth: 2,
-            color: AppColors.blue600,
-            trackColor: AppColors.blue100,
+            color: colorScheme.primary,
+            trackColor: colorScheme.primaryContainer,
           ),
         ),
         const SizedBox(width: AppSpacing.sm),
-        _buildWaveDots(),
+        _buildWaveDots(context),
         const SizedBox(width: AppSpacing.sm),
         Expanded(
           child: Text(
             context.l10n.homeTranscribing,
-            style: const TextStyle(
+            style: TextStyle(
               fontSize: 14,
-              color: AppColors.blue600,
+              color: colorScheme.primary,
               fontWeight: FontWeight.w600,
             ),
             overflow: TextOverflow.ellipsis,
@@ -188,7 +192,9 @@ class HomeComposerStack extends StatelessWidget {
     );
   }
 
-  Widget _buildWaveDots() {
+  Widget _buildWaveDots(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     return Row(
       crossAxisAlignment: CrossAxisAlignment.end,
       children: List.generate(3, (index) {
@@ -197,7 +203,7 @@ class HomeComposerStack extends StatelessWidget {
           width: 3,
           height: 6 + index * 2,
           decoration: BoxDecoration(
-            color: AppColors.blue500,
+            color: colorScheme.primary,
             borderRadius: BorderRadius.circular(2),
           ),
         );