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/app_button.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 
 import '../../core/theme/design_tokens.dart';
+import 'app_loading_indicator.dart';
 
 class AppButton extends StatelessWidget {
   const AppButton({
@@ -47,13 +48,10 @@ class AppButton extends StatelessWidget {
             padding: const EdgeInsets.symmetric(horizontal: AppSpacing.xl),
           ),
           child: isLoading
-              ? SizedBox(
-                  width: 18,
-                  height: 18,
-                  child: CircularProgressIndicator(
-                    strokeWidth: 2.2,
-                    color: AppColors.authSecondaryButtonText,
-                  ),
+              ? const AppLoadingIndicator(
+                  variant: AppLoadingVariant.button,
+                  color: AppColors.authSecondaryButtonText,
+                  trackColor: AppColors.authSecondaryButtonBorder,
                 )
               : Text(
                   text,
@@ -115,13 +113,10 @@ class AppButton extends StatelessWidget {
             ),
           ),
           child: isLoading
-              ? const SizedBox(
-                  width: 18,
-                  height: 18,
-                  child: CircularProgressIndicator(
-                    strokeWidth: 2.2,
-                    color: AppColors.authPrimaryButtonText,
-                  ),
+              ? const AppLoadingIndicator(
+                  variant: AppLoadingVariant.button,
+                  color: AppColors.authPrimaryButtonText,
+                  trackColor: AppColors.blue400,
                 )
               : Text(
                   text,