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

apps/lib/shared/widgets/app_sheet_input_field.dart

@@ -50,16 +50,17 @@ class _AppSheetInputFieldState extends State<AppSheetInputField> {
 
   @override
   Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
         Text(
           widget.label,
-          style: const TextStyle(
+          style: TextStyle(
             fontFamily: 'Inter',
             fontSize: 14,
             fontWeight: FontWeight.w600,
-            color: AppColors.slate700,
+            color: colorScheme.onSurfaceVariant,
           ),
         ),
         const SizedBox(height: AppSpacing.sm),
@@ -67,17 +68,17 @@ class _AppSheetInputFieldState extends State<AppSheetInputField> {
           duration: const Duration(milliseconds: 140),
           curve: Curves.easeOut,
           decoration: BoxDecoration(
-            color: AppColors.slate50,
+            color: colorScheme.surfaceContainerLowest,
             borderRadius: BorderRadius.circular(AppRadius.md),
             border: Border.all(
               color: _isFocused
-                  ? AppColors.borderQuaternary
-                  : AppColors.borderSecondary,
+                  ? colorScheme.primary
+                  : colorScheme.outlineVariant,
             ),
             boxShadow: _isFocused
                 ? [
                     BoxShadow(
-                      color: AppColors.blue200.withValues(alpha: 0.35),
+                      color: colorScheme.secondary.withValues(alpha: 0.35),
                       blurRadius: AppRadius.sm,
                       offset: const Offset(0, AppSpacing.xs / 2),
                     ),
@@ -91,7 +92,9 @@ class _AppSheetInputFieldState extends State<AppSheetInputField> {
             maxLines: widget.maxLines,
             decoration: InputDecoration(
               hintText: widget.hint,
-              hintStyle: const TextStyle(color: AppColors.slate400),
+              hintStyle: TextStyle(
+                color: colorScheme.onSurfaceVariant.withValues(alpha: 0.6),
+              ),
               border: InputBorder.none,
               contentPadding: const EdgeInsets.symmetric(
                 horizontal: AppSpacing.md,