feat(flutter): 应用浅色暖橙视觉主题

lib/pages/auth/auth_view.dart

@@ -141,7 +141,7 @@ class _AuthPageState extends State<AuthPage> {
   Widget build(BuildContext context) {
     final l10n = AppLocalizations.of(context)!;
     return Theme(
-      data: AppTheme.dark(),
+      data: AppTheme.light(),
       child: Scaffold(
         resizeToAvoidBottomInset: true,
         backgroundColor: AppColors.ink,
@@ -332,7 +332,7 @@ class _AuthPageState extends State<AuthPage> {
       Text(
         l10n.authLandingSubtitle,
         textAlign: TextAlign.center,
-        style: const TextStyle(color: Color(0xFF9A96A3), fontSize: 11),
+        style: const TextStyle(color: AppColors.subtle, fontSize: 11),
       ),
       const SizedBox(height: 22),
       _AuthEntryButton(
@@ -358,7 +358,7 @@ class _AuthPageState extends State<AuthPage> {
         key: const Key('auth-legal'),
         textAlign: TextAlign.center,
         style: const TextStyle(
-          color: Color(0xFF6B6772),
+          color: AppColors.muted,
           fontSize: 9,
           height: 1.6,
         ),
@@ -442,8 +442,7 @@ class _AuthEntryButton extends StatelessWidget {
           child: Row(
             mainAxisAlignment: MainAxisAlignment.center,
             children: [
-              if (icon != null)
-                Icon(icon, size: 16, color: foreground),
+              if (icon != null) Icon(icon, size: 16, color: foreground),
               if (icon != null) const SizedBox(width: 7),
               Flexible(
                 child: Text(