fix(mining-app): update splash page theme and fix token refresh

- Update splash_page.dart to orange theme (#FF6B00) matching other pages
- Change app name from "榴莲挖矿" to "榴莲生态"
- Fix refreshTokenIfNeeded to properly throw on failure instead of
  silently calling logout (which caused Riverpod ref errors)
- Clear local storage directly on refresh failure without remote API call

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-app/lib/presentation/pages/splash/splash_page.dart

@@ -2,7 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import '../../../core/router/routes.dart';
-import '../../../core/constants/app_colors.dart';
 import '../../providers/user_providers.dart';
 
 class SplashPage extends ConsumerStatefulWidget {
@@ -13,6 +12,12 @@ class SplashPage extends ConsumerStatefulWidget {
 }
 
 class _SplashPageState extends ConsumerState<SplashPage> {
+  // 设计色彩 - 与导航页面统一
+  static const Color _orange = Color(0xFFFF6B00);
+  static const Color _darkText = Color(0xFF1F2937);
+  static const Color _grayText = Color(0xFF6B7280);
+  static const Color _serenade = Color(0xFFFFF7ED);
+
   @override
   void initState() {
     super.initState();
@@ -49,7 +54,7 @@ class _SplashPageState extends ConsumerState<SplashPage> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      backgroundColor: AppColors.primary,
+      backgroundColor: Colors.white,
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
@@ -58,20 +63,20 @@ class _SplashPageState extends ConsumerState<SplashPage> {
               width: 100,
               height: 100,
               decoration: BoxDecoration(
-                color: Colors.white,
-                borderRadius: BorderRadius.circular(20),
+                color: _serenade,
+                borderRadius: BorderRadius.circular(24),
               ),
               child: const Icon(
                 Icons.eco,
                 size: 60,
-                color: AppColors.primary,
+                color: _orange,
               ),
             ),
             const SizedBox(height: 24),
             const Text(
-              '榴莲挖矿',
+              '榴莲生态',
               style: TextStyle(
-                color: Colors.white,
+                color: _darkText,
                 fontSize: 28,
                 fontWeight: FontWeight.bold,
               ),
@@ -80,14 +85,18 @@ class _SplashPageState extends ConsumerState<SplashPage> {
             const Text(
               '绿色财富 共享未来',
               style: TextStyle(
-                color: Colors.white70,
+                color: _grayText,
                 fontSize: 16,
               ),
             ),
             const SizedBox(height: 48),
-            const CircularProgressIndicator(
-              color: Colors.white,
-              strokeWidth: 2,
+            const SizedBox(
+              width: 24,
+              height: 24,
+              child: CircularProgressIndicator(
+                color: _orange,
+                strokeWidth: 2,
+              ),
             ),
           ],
         ),

frontend/mining-app/lib/presentation/providers/user_providers.dart

@@ -181,14 +181,19 @@ class UserNotifier extends StateNotifier<UserState> {
   }
 
   Future<void> refreshTokenIfNeeded() async {
-    if (state.refreshToken == null) return;
+    if (state.refreshToken == null) {
+      throw Exception('No refresh token available');
+    }
     try {
       final newAccessToken = await _authDataSource.refreshToken(state.refreshToken!);
       final prefs = await SharedPreferences.getInstance();
       await prefs.setString('access_token', newAccessToken);
       state = state.copyWith(accessToken: newAccessToken);
     } catch (e) {
-      await logout();
+      // 清除本地存储，不调用远程logout API（可能网络不可用）
+      await _clearStorage();
+      state = UserState();
+      rethrow;
     }
   }