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_floating_header.dart

@@ -22,6 +22,8 @@ class HomeFloatingHeader extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     return Container(
       key: homeFloatingHeaderKey,
       padding: const EdgeInsets.fromLTRB(
@@ -30,9 +32,9 @@ class HomeFloatingHeader extends StatelessWidget {
         AppSpacing.lg,
         AppSpacing.xs,
       ),
-      decoration: const BoxDecoration(
-        color: AppColors.homeToolbarSurface,
-        border: Border(bottom: BorderSide(color: AppColors.homeToolbarBorder)),
+      decoration: BoxDecoration(
+        color: colorScheme.surface.withValues(alpha: 0.95),
+        border: Border(bottom: BorderSide(color: colorScheme.outlineVariant)),
       ),
       child: Stack(
         alignment: Alignment.center,
@@ -61,7 +63,7 @@ class HomeFloatingHeader extends StatelessWidget {
               ),
             ],
           ),
-          const IgnorePointer(
+          IgnorePointer(
             child: Padding(
               padding: EdgeInsets.symmetric(horizontal: AppSpacing.xl * 3),
               child: Text(
@@ -72,7 +74,7 @@ class HomeFloatingHeader extends StatelessWidget {
                 style: TextStyle(
                   fontSize: AppSpacing.lg + (AppSpacing.xs / 2),
                   fontWeight: FontWeight.w600,
-                  color: AppColors.slate800,
+                  color: colorScheme.onSurface,
                 ),
               ),
             ),
@@ -91,6 +93,8 @@ class _HeaderIconButton extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     return IconButton(
       visualDensity: VisualDensity.compact,
       padding: const EdgeInsets.all(AppSpacing.xs),
@@ -99,7 +103,7 @@ class _HeaderIconButton extends StatelessWidget {
         minHeight: AppSpacing.xxl + AppSpacing.lg,
       ),
       onPressed: onPressed,
-      icon: Icon(icon, size: AppSpacing.xxl, color: AppColors.slate900),
+      icon: Icon(icon, size: AppSpacing.xxl, color: colorScheme.onSurface),
     );
   }
 }
@@ -112,6 +116,8 @@ class _MessagesButton extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+
     return IconButton(
       visualDensity: VisualDensity.compact,
       padding: const EdgeInsets.all(AppSpacing.xs),
@@ -123,10 +129,10 @@ class _MessagesButton extends StatelessWidget {
       icon: Stack(
         clipBehavior: Clip.none,
         children: [
-          const Icon(
+          Icon(
             LucideIcons.messageSquare,
             size: AppSpacing.xxl,
-            color: AppColors.slate900,
+            color: colorScheme.onSurface,
           ),
           if (unreadCount > 0)
             Positioned(
@@ -138,7 +144,7 @@ class _MessagesButton extends StatelessWidget {
                   vertical: AppSpacing.xs / 2,
                 ),
                 decoration: BoxDecoration(
-                  color: AppColors.red500,
+                  color: colorScheme.error,
                   borderRadius: BorderRadius.circular(AppSpacing.sm),
                 ),
                 constraints: const BoxConstraints(
@@ -148,10 +154,10 @@ class _MessagesButton extends StatelessWidget {
                 child: Text(
                   unreadCount > 99 ? '99+' : unreadCount.toString(),
                   textAlign: TextAlign.center,
-                  style: const TextStyle(
+                  style: TextStyle(
                     fontSize: AppSpacing.sm + (AppSpacing.xs / 2),
                     fontWeight: FontWeight.w600,
-                    color: AppColors.white,
+                    color: colorScheme.onError,
                   ),
                 ),
               ),