feat: 新增 AppLoadingIndicator 和 AppPressable 组件

- 新增 AppLoadingIndicator 加载指示器组件
- 新增 AppPressable 按压反馈组件
- 新增 AppSheetInputField 输入框组件
- 更新 AppButton 和其他共享组件

apps/lib/shared/widgets/message_composer.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:lucide_icons/lucide_icons.dart';
 
 import '../../core/theme/design_tokens.dart';
+import 'app_loading_indicator.dart';
 
 enum MessageComposerMode { text, holdToSpeak }
 
@@ -125,13 +126,12 @@ class MessageComposer extends StatelessWidget {
                 visualDensity: VisualDensity.compact,
                 onPressed: onTapRightAction,
                 icon: _isTranscribing
-                    ? const SizedBox(
-                        width: AppSpacing.lg,
-                        height: AppSpacing.lg,
-                        child: CircularProgressIndicator(
-                          strokeWidth: AppSpacing.xs / 2,
-                          color: AppColors.blue600,
-                        ),
+                    ? const AppLoadingIndicator(
+                        variant: AppLoadingVariant.inline,
+                        size: AppSpacing.lg,
+                        strokeWidth: AppSpacing.xs / 2,
+                        color: AppColors.blue600,
+                        trackColor: AppColors.blue100,
                       )
                     : Icon(
                         _resolveRightIcon(),